Document:

<PAGE>

                                                                    Exhibit 10.5

                                                                  EXECUTION COPY

                               FOURTH AMENDMENT
                                      TO
                      AMENDED AND RESTATED LOAN AGREEMENT

     THIS FOURTH AMENDMENT TO AMENDED AND RESTATED LOAN AGREEMENT, dated as of
the 23rd of January, 2001 (this "Amendment"), is made by and among AMERICAN
                                 ---------
TOWER, L.P., a Delaware limited partnership, AMERICAN TOWERS, INC., a Delaware
corporation, VERESTAR, INC., a Delaware corporation (collectively, the
"Borrowers"), THE FINANCIAL INSTITUTIONS SIGNATORIES HERETO and TORONTO DOMINION
 ---------
(TEXAS), INC., as administrative agent (in such capacity, the "Administrative
                                                               --------------
Agent").
-----

                              W I T N E S S E T H:
                              - - - - - - - - - -

     WHEREAS, the Borrowers, the Lenders (as defined therein), the Issuing Bank
(as defined therein) and the Administrative Agent are all parties to that
certain Amended and Restated Loan Agreement dated as of January 6, 2000 (as
previously amended and as hereafter amended, modified, restated and supplemented
from time to time, the "Loan Agreement"); and
                        --------------

     WHEREAS, the Borrowers have requested amendments to certain provisions of
the Loan Agreement, and, subject to the terms and conditions set forth herein,
the Lenders and the Administrative Agent are willing to amend certain provisions
of the Loan Agreement as more specifically set forth herein;

     NOW, THEREFORE, in consideration of the premises set forth above, and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree that all capitalized terms used
and not defined herein shall have the meanings ascribed to such terms in the
Loan Agreement, and further hereby agree as follows:

     1.   Amendments to Article 1.
          -----------------------

     (a)  Section 1.1 of the Loan Agreement, Definitions, is hereby amended by
                                             -----------
deleting the definitions of "Capital Raise Proceeds" and "Pro Forma Debt
                             ----------------------       --------------
Service" in their entireties and by substituting the following definitions in
-------
lieu thereof:

          " 'Capital Raise Proceeds' shall mean, (a) at any time prior to the
             ----------------------
     Borrowing Base Termination Date, (i) fifty percent (50%) of the net cash
     proceeds of any public or private sale or issuance of the Capital Stock of
     the Parent in excess of $100,000,000.00 in the aggregate after the
     Agreement Date, and (ii) one hundred percent (100%) of the net cash
     proceeds of any public or private sale or issuance of debt instruments of
     the Parent, any of the Borrowers or any of the Restricted Subsidiaries
     (other than (A) net proceeds in an amount not to exceed $2,000,000.00 in
     the aggregate after the Agreement Date from the sale or issuance of Capital
     Stock in connection with any employee stock option plan of
<PAGE>

     any such Person, (B) debt among the Borrowers and the Restricted
     Subsidiaries, or any of them, (C) the Loans, (D) proceeds received from
     Capital Stock issued in connection with an Acquisition hereunder, and (E)
     the proceeds of the Senior Notes due 2009), (b) at any time on or after the
     Borrowing Base Termination Date when the Leverage Ratio is greater than
     5.00 to 1.00 fifty percent (50%) of the net proceeds of any public or
     private sale or issuance of debt instruments of the Parent, any of the
     Borrowers or any of the Restricted Subsidiaries (other than (A) debt among
     the Borrowers and the Restricted Subsidiaries, or any of them, or (B) the
     Loans), or, (c) at any other time, zero (0)."

          " 'Pro Forma Debt Service' shall mean with respect to the twelve (12)
             ----------------------
     calendar month period following the calculation date, and after giving
     effect to any Interest Hedge Agreements and LIBOR Advances, the sum of the
     amount of all of the following with respect to the Borrowers and the
     Restricted Subsidiaries, on a consolidated basis:  (a) scheduled payments
     of principal on Indebtedness for Money Borrowed (determined, with respect
     to the Revolving Loans only, as the difference between the outstanding
     principal amount of the Revolving Loans and Letter of Credit Obligations on
     the calculation date and the amount the Revolving Loan Commitments will be
     on the last day of such period) for such period; (b) Interest Expense for
     such period; (c) fees payable under this Agreement for such period; (d)
     other payments payable by such Persons during such period in respect of
     Indebtedness for Money Borrowed (other than voluntary repayments); and (e)
     after the Interest Reserve and/or the 2001 Interest Reserve, as applicable,
     has been applied in full pursuant to the terms hereof, all Restricted
     Payments to be made by the Borrowers to the Parent which will be necessary
     to make interest payments on the (i) Convertible Notes and/or (ii) Senior
     Notes due 2009 during such period.  For purposes of this definition, where
     interest payments for the twelve (12) month period immediately succeeding
     the calculation date are not fixed by way of Interest Hedge Agreements,
     LIBOR Advances, or otherwise for the entire period, interest shall be
     calculated on such Indebtedness for Money Borrowed for periods for which
     interest payments are not so fixed at the lesser of (i) the LIBOR Basis
     (based on the then current adjustment under Section 2.3(f) hereof) for a
     LIBOR Advance having an Interest Period of six (6) months as determined on
     the date of calculation and (ii) the Base Rate Basis as in effect on the
     date of calculation; provided, however, that if such LIBOR Basis cannot be
                          --------  -------
     determined in the reasonable opinion of the Administrative Agent, such
     interest shall be calculated using the Base Rate Basis as then in effect."

     (b)  Section 1.1 of the Loan Agreement, Definitions, is hereby further
                                             -----------
amended by inserting therein the following new definitions of "2001 Interest
                                                               -------------
Reserve" and "Senior Notes due 2009" in the proper alphabetical order:
-------       ---------------------

          " '2001 Interest Reserve' shall mean an escrow account (a) maintained
             ---------------------
     by the Parent in a manner substantially similar to the Interest Reserve,
     (b) established with the proceeds of the Senior Notes due 2009 which shall
     be used to make interest payments on the Senior Notes due 2009 through
     February 2002."

                                      -2-
<PAGE>

          " 'Senior Notes due 2009 ' shall mean the senior notes due 2009 issued
             ----------------------
     on or after January 1, 2001 (a) which are unsecured and not guaranteed, (b)
     which are issued by the Parent, (c) which have a maturity date which is no
     earlier than twelve (12) months after the Term Loan B Maturity Date, (d)
     which have terms and conditions which are substantially similar to those
     set forth in the Preliminary Confidential Offering Circular dated January
     17, 2001, and (e) the net cash proceeds of which (other than amounts
     required for the 2001 Interest Reserve) are contributed to the Borrowers as
     equity."

     2.   Amendments to Article 7. Section 7.7 of the Loan Agreement, Restricted
          -----------------------                                     ----------
Payments, is hereby amended by deleting such section in its entirety and by
--------
substituting in lieu thereof the following new section:

          "Section 7.7  Restricted Payments.  The Borrowers shall not, and shall
                        -------------------
     not permit any of the Restricted Subsidiaries to, directly or indirectly
     declare or make any Restricted Payment; provided, however, that so long as
                                             --------  -------
     no Default or Event of Default hereunder then exists or would be caused
     thereby, the Borrowers may make, (a) subject to Section 2.7(b)(iv) hereof,
     cash distributions in an aggregate amount for all Borrowers not to exceed
     fifty percent (50%) of Excess Cash Flow for the immediately preceding
     calendar year, on or after April 15th of each calendar year commencing on
     April 15, 2004; and (b)  distributions to the Parent to make scheduled
     principal and interest payments on the Convertible Notes and the Senior
     Notes due 2009; provided, however, that (x) all funds in the Interest
                     --------- -------
     Reserve shall have been used to make all interest payments on the
     Convertible Notes due on or prior to October 15, 2001 and (y) all funds in
     the 2001 Interest Reserve shall have been used in full to make all interest
     payments on the Senior Notes due 2009 due on or prior to February 15,
     2002."

     3.   Amendment to Article 8.  Section 8.1 of the Loan Agreement, Events of
          ----------------------                                      ---------
Default, is hereby amended by deleting clause (p) thereof in its entirety and
-------
substituting in lieu thereof new clause (p) as follows:

          "(p)  the Parent shall incur or permit to remain outstanding any
     Indebtedness for Money Borrowed other than (i) the Convertible Notes, (ii)
     the Senior Notes due 2009 in an aggregate principal amount not to exceed at
     any time outstanding $1,000,000,000, (iii) any refinancing of the foregoing
     in an amount not exceeding the outstanding principal amount of the
     Indebtedness being refinanced on the date of such refinancing and otherwise
     having terms no less favorable in any material respect to the Lenders than
     the Indebtedness being refinanced, (iv) that certain Guaranty Agreement
     dated as of February 10, 2000 made by the Parent in favor of TV Azteca and
     Television Azteca, S.A. de C.V., a sociedad anonima de capital variable
     organized under the laws of Mexico, and (v) that certain Guaranty dated
     November 30, 1999 made by the Parent in favor of ICG Holdings; provided,
                                                                    --------
     however, it shall be an Event of Default hereunder unless,
     -------
     contemporaneously with the issuance of the Senior Notes due 2009, the
     Parent establishes (or causes to be established) the 2001 Interest Reserve
     from the proceeds of the Senior Notes due 2009 (which amounts shall not be
     required to be contributed as equity to the Borrowers under Section 8.1(q)
     hereof or otherwise); or"

                                      -3-
<PAGE>

     4.   No Other Amendment.  Except for the amendments set forth above,
          ------------------
the text of the Loan Agreement and all other Loan Documents shall remain
unchanged and in full force and effect.  No amendment or waiver by the
Administrative Agent, the Issuing Bank or the Lenders under the Loan Agreement
or any other Loan Document is granted or intended except as expressly set forth
herein, and the Administrative Agent, the Issuing Bank and the Lenders expressly
reserve the right to require strict compliance in all other respects (whether or
not in connection with any Requests for Advance).  Except as set forth herein,
the amendments agreed to herein shall not constitute a modification of the Loan
Agreement or any of the other Loan Documents, or a course of dealing with the
Administrative Agent, the Issuing Bank and the Lenders at variance with the Loan
Agreement or any of the other Loan Documents, such as to require further notice
by the Administrative Agent, the Issuing Bank, the Lenders or the Majority
Lenders to require strict compliance with the terms of the Loan Agreement and
the other Loan Documents in the future.

     5.   Representations and Warranties.  The Borrowers hereby represent and
          ------------------------------
warrant to and in favor of the Administrative Agent, for itself and on behalf of
the Lenders as follows:

          (a)  Each representation and warranty set forth in Article 4 of the
     Loan Agreement, as amended hereby, is hereby restated and affirmed as true
     and correct in all material respects as of the date hereof, except to the
     extent (i) previously fulfilled in accordance with the terms of the Loan
     Agreement, as amended hereby, (ii) the Borrowers have provided the
     Administrative Agent updates to information provided to the Administrative
     Agent in accordance with the terms of such representations and warranties,
     or (iii) relating specifically to the Agreement Date or otherwise
     inapplicable;

          (b)  Each of the Borrowers has the power and authority (i) to enter
     into this Amendment, and (ii) to do all acts and things as are required or
     contemplated hereunder to be done, observed and performed by it;

          (c)  This Amendment has been duly authorized, validly executed and
     delivered by one or more Authorized Signatories of each of the Borrowers,
     and constitutes the legal, valid and binding obligations of the Borrower,
     enforceable against each of the Borrowers in accordance with its terms,
     subject, as to enforcement of remedies, to the following qualifications:
     (i) an order of specific performance and an injunction are discretionary
     remedies and, in particular, may not be available where damages are
     considered an adequate remedy at law, and (ii) enforcement may be limited
     by bankruptcy, insolvency, liquidation, reorganization, reconstruction and
     other similar laws affecting enforcement of creditors' rights generally
     (insofar as any such law relates to the bankruptcy, insolvency or similar
     event of the Borrowers); and

          (d)  The execution and delivery of this Amendment and performance by
     the Borrowers under the Loan Agreement, as amended hereby, does not and
     will not require the consent or approval of any regulatory authority or
     governmental authority or agency having jurisdiction over the Borrowers
     which has not already been obtained, nor be in

                                      -4-
<PAGE>

     contravention of or in conflict with the articles of incorporation or by-
     laws of the Borrowers, or any provision of any statute, judgment, order,
     indenture, instrument, agreement, or undertaking, to which the Borrowers
     are party or by which the Borrowers 'assets or properties are bound.

     6.   Condition Precedent. The effectiveness of this Amendment is subject to
          -------------------
receipt by the Administrative Agent of (a) executed signature pages to this
Amendment from the Majority Lenders and (b) the amendment fee payable by the
Borrower to each Lender executing this Amendment.

     7.   Counterparts. This Amendment may be executed in any number of
          ------------
counterparts, each of which shall be deemed to be an original, but all such
separate counterparts shall together constitute but one and the same instrument.

     8.   Governing Law. This Amendment shall be construed in accordance with
          -------------
and governed by the laws of the State of New York.

     9.   Severability. Any provision of this Amendment which is prohibited or
          ------------
unenforceable shall be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining provisions hereof in that
jurisdiction or affecting the validity or enforceability of such provision in
any other jurisdiction.

               [REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]

                                      -5-
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Amendment or
caused it to be executed by their duly authorized officers, all as of the day
and year first above written.

BORROWERS:                  AMERICAN TOWER, L.P., a Delaware limited partnership
                            By ATC GP INC., its General Partner

                            By:/s/ Joseph L. Winn
                               ------------------------------------
                               Name:  Joseph L. Winn
                                    -------------------------------
                               Title:  CFO
                                    -------------------------------

                            AMERICAN TOWERS, INC., a Delaware corporation

                            By:/s/ Joseph L. Winn
                               ------------------------------------
                               Name:  Joseph L. Winn
                                    -------------------------------
                               Title:  CFO
                                    -------------------------------

                            VERESTAR, INC., a Delaware corporation

                            By:/s/ Joseph L. Winn
                               ------------------------------------
                               Name:  Joseph L. Winn
                                    -------------------------------
                               Title:  CFO
                                    -------------------------------

<PAGE>

ADMINISTRATIVE AGENT
AND LENDERS:             TORONTO DOMINION (TEXAS), INC., as Administrative
                         Agent, for itself, the Issuing Bank and the Lenders, as
                         Issuing Bank and as a Lender

                         By:  /s/ Jano Mott
                            ---------------------------
                            Name:  Jano Mott
                                 ----------------------
                            Title: Vice President
                                 ----------------------

<PAGE>

                            THE BANK OF NEW YORK, as a Lender

                            By:  /s/ Geoffrey C. Brooks
                               ----------------------------
                               Name:  Geoffrey C. Brooks
                                    -----------------------
                               Title: Senior Vice President
                                    -----------------------

<PAGE>

                            THE CHASE MANHATTAN BANK, as a Lender

                            By:   /s/ William E. Rottino
                               -------------------------------
                               Name:   William E. Rottino
                                    --------------------------
                               Title:  Vice President
                                    --------------------------

<PAGE>

                            CREDIT SUISSE FIRST BOSTON, as Lender

                            By:_______________________________________
                               Name:__________________________________
                               Title:_________________________________

                            By:_______________________________________
                               Name:__________________________________
                               Title:_________________________________
<PAGE>

                            ALLFIRST BANK, as a Lender

                            By: /s/ Signature Illegible
                                --------------------------------------
                               Name:
                                    ----------------------------------
                               Title: Vice President
                                     ---------------------------------
<PAGE>

                             ALLSTATE LIFE INSURANCE COMPANY, as a Lender

                             By:   /s/ Jerry D. Zinkula
                                ----------------------------------
                                Name:   Jerry D. Zinkula
                                     -----------------------------
                                Title:  Authorized Signatory
                                     -----------------------------

                             By:   /s/ Patricia W. Wilson
                                ----------------------------------
                                Name:   Patricia W. Wilson
                                     -----------------------------
                                Title:  Authorized Signatory
                                     -----------------------------

                             AIMCO CDO SERIES 2000-A, as a Lender

                             By:   /s/ Jerry D. Zinkula
                                ----------------------------------
                                Name:   Jerry D. Zinkula
                                     -----------------------------
                                Title:  Authorized Signatory
                                     -----------------------------

                             By:   /s/ Patricia W. Wilson
                                ----------------------------------
                                Name:   Patricia W. Wilson
                                     -----------------------------
                                Title:  Authorized Signatory
                                     -----------------------------

<PAGE>

                             AMARA-2 FINANCE, LTD., as a Lender
                             By: INVESCO Senior Secured Management, Inc.,
                             as Subadvisor

                             By:    /s/ Kathleen A. Lenarcic
                                ---------------------------------
                                Name:   Kathleen A. Lenarcic
                                     ----------------------------
                                Title:  Authorized Signatory
                                     ----------------------------

                             AVALON CAPITAL LTD., as a Lender
                             By: INVESCO Senior Secured Management, Inc.,
                             as Portfolio Advisor

                             By:    /s/ Kathleen A. Lenarcic
                                ---------------------------------
                                Name:   Kathleen A. Lenarcic
                                     ----------------------------
                                Title:  Authorized Signatory
                                     ----------------------------

                             AVALON CAPITAL LTD. 2, as a Lender
                             By: INVESCO Senior Secured Management, Inc.,
                             as Portfolio Advisor

                             By:    /s/ Kathleen A. Lenarcic
                                ---------------------------------
                                Name:   Kathleen A. Lenarcic
                                     ----------------------------
                                Title:  Authorized Signatory
                                     ----------------------------

                             CERES II FINANCE LTD., as a Lender
                             By: INVESCO Senior Secured Management, Inc.,
                             as Sub-Managing Agent (Financial)

                             By:    /s/ Kathleen A. Lenarcic
                                ---------------------------------
                                Name:   Kathleen A. Lenarcic
                                     ----------------------------
                                Title:  Authorized Signatory
                                     ----------------------------

<PAGE>

                             CHARTER VIEW PORTFOLIO, as a Lender
                             By: INVESCO Senior Secured Management, Inc.,
                             as Investment Advisor

                             By:    /s/ Kathleen A. Lenarcic
                                ----------------------------------
                                Name:   Kathleen A. Lenarcic
                                     -----------------------------
                                Title:  Authorized Signatory
                                     -----------------------------

                             TRITON CDO IV, LIMITED, as a Lender
                             By: INVESCO Senior Secured Management, Inc.,
                             as Investment Advisor

                             By:    /s/ Kathleen A. Lenarcic
                                ---------------------------------
                                Name:   Kathleen A. Lenarcic
                                     ----------------------------
                                Title:  Authorized Signatory
                                     ----------------------------

<PAGE>

                             ARCHIMEDES FUNDING, L.L.C., as a Lender
                             By: ING Capital Advisors LLC, as Collateral
                             Manager

                             By:    /s/ Steven Gorski
                                ---------------------------------
                                Name:   Steven Gorski
                                     ----------------------------
                                Title:  Senior Credit Analyst
                                     ----------------------------

                             ARCHIMEDES FUNDING II, LTD., as a Lender
                             By: ING Capital Advisors LLC, as Collateral
                             Manager

                             By:    /s/ Steven Gorski
                                ---------------------------------
                                Name:   Steven Gorski
                                     ----------------------------
                                Title:  Senior Credit Analyst
                                     ----------------------------

                             ARCHIMEDES FUNDING III, LTD., as a Lender
                             By: ING Capital Advisors LLC, as Collateral
                             Manager

                             By:    /s/ Steven Gorski
                                ---------------------------------
                                Name:   Steven Gorski
                                     ----------------------------
                                Title:  Senior Credit Analyst
                                     ----------------------------

                             THE ING CAPITAL SENIOR SECURED HIGH INCOME
                             FUND, L.P., as Assignee
                             By: ING Capital Advisors LLC, as Investment
                             Advisor

                             By:    /s/ Steven Gorski
                                ---------------------------------
                                Name:   Steven Gorski
                                     ----------------------------
                                Title:  Senior Credit Analyst
                                     ----------------------------

<PAGE>

                             SEQUILS-ING I (HBDGM), LTD., as Assignee
                             By: ING Capital Advisors LLC, as Collateral
                             Manager

                             By:    /s/ Steven Gorski
                                --------------------------------
                                Name:   Steven Gorski
                                     ---------------------------
                                Title:  Senior Credit Analyst
                                     ---------------------------

<PAGE>

                             ATHENA CDO, LIMITED, as a Lender
                             By: Pacific Investment Management Company,
                             LLC, as its
                             Investment Advisor

                             By:    /s/ Mohan V. Phansalkar
                                -----------------------------------
                                Name:   Mohan V. Phansalkar
                                     ------------------------------
                                Title:  Senior Vice President
                                     ------------------------------

                             BEDFORD CDO, LIMITED, as a Lender
                             By: Pacific Investment Management Company,
                             LLC, as its
                             Investment Advisor

                             By:    /s/ Mohan V. Phansalkar
                                -----------------------------------
                                Name:   Mohan V. Phansalkar
                                     ------------------------------
                                Title:  Senior Vice President
                                     ------------------------------

                             CAPTIVA III FINANCE LTD., as a Lender
                             As advised by Pacific Investment Management
                             Company, LLC

                             By:    /s/ David Dyer
                                ----------------------------------
                                Name:   David Dyer
                                     -----------------------------
                                Title:  Director
                                     -----------------------------

                             CAPTIVA IV FINANCE LTD., as a Lender
                             As advised by Pacific Investment Management
                             Company, LLC

                             By:    /s/ David Dyer
                                ----------------------------------
                                Name:   David Dyer
                                     -----------------------------
                                Title:  Director
                                     -----------------------------
<PAGE>

                             CATALINA CDO LTD., as a Lender
                             By: Pacific Investment Management Company,
                             LLC, as its Investment Advisor

                             By:    /s/ Mohan V. Phansalkar
                                --------------------------------
                                Name:   Mohan V. Phansalkar
                                     ---------------------------
                                Title:  Senior Vice President
                                     ---------------------------

                             DELANO COMPANY, as a Lender
                             By: Pacific Investment Management Company,
                             LLC, as its Investment Advisor

                             By:    /s/ Mohan V. Phansalkar
                                --------------------------------
                                Name:   Mohan V. Phansalkar
                                     ---------------------------
                                Title:  Senior Vice President
                                     ---------------------------

                             JISSEKIKUN FUNDING, LTD., as a Lender
                             By: Pacific Investment Management Company,
                             LLC, as its Investment Advisor

                             By:    /s/ Mohan V. Phansalkar
                                --------------------------------
                                Name:   Mohan V. Phansalkar
                                     ---------------------------
                                Title:  Senior Vice President
                                     ---------------------------

                             ROYALTON COMPANY, as a Lender
                             By: Pacific Investment Management Company,
                             LLC, as its Investment Advisor

                             By:    /s/ Mohan V. Phansalkar
                                --------------------------------
                                Name:   Mohan V. Phansalkar
                                     ---------------------------
                                Title:  Senior Vice President
                                     ---------------------------

<PAGE>

                             TRIGON HEALTHCARE INC. (ACCT 674), as a Lender
                             By: Pacific Investment Management Company, as
                             its Investment Advisor, acting through The Bank
                             of New York in the Nominee Name of Hare & Co.

                             By:    /s/ Mohan V. Phansalkar
                                ------------------------------------
                                Name:   Mohan V. Phansalkar
                                     -------------------------------
                                Title:  Senior Vice President
                                     -------------------------------

<PAGE>

                             BALANCED HIGH YIELD FUND I LTD., as a Lender
                             By: BHF (USA) Capital Corporation
                             Acting as Attorney-in-Fact

                             By:_______________________________________________
                                Name:__________________________________________
                                Title:_________________________________________

                             By:_______________________________________________
                                Name:__________________________________________
                                Title:_________________________________________

                             BALANCED HIGH YIELD FUND II, LTD., as a Lender
                             By: BHF (USA) Capital Corporation
                             Acting as Attorney-in-Fact

                             By:_______________________________________________
                                Name:__________________________________________
                                Title:_________________________________________

                             By:_______________________________________________
                                Name:__________________________________________
                                Title:_________________________________________

<PAGE>

                                   BANK OF AMERICA, N.A., as a Lender

                                   By:   /s/ Todd Shipley
                                      ----------------------------
                                      Name:   Todd Shipley
                                           -----------------------
                                      Title:  Managing Director
                                           -----------------------
<PAGE>

                                   BANK OF MONTREAL, as a Lender

                                   By:    /s/ Sarah Kim
                                      -----------------------------
                                      Name:   Sarah Kim
                                           ------------------------
                                      Title:  Director
                                           ------------------------
<PAGE>

                                   THE BANK OF NOVA SCOTIA, as a Lender

                                   By:    /s/ Paul A. Weissenberger
                                      -------------------------------
                                      Name:   Paul A. Weissenberger
                                           --------------------------
                                      Title:  Authorized Signatory
                                           --------------------------
<PAGE>

                                   BANK OF SCOTLAND, as a Lender

                                   By:    /s/ Joseph Fratus
                                      ---------------------------
                                      Name:   Joseph Fratus
                                           ----------------------
                                      Title:  Vice President
                                           ----------------------
<PAGE>

                                   BANK UNITED, as a Lender

                                   By: /s/ Phil Green
                                       -------------------------------
                                       Name: Phil Green
                                       Title: Director Commercial Syndications
<PAGE>

                                      BANKERS TRUST COMPANY, as a Lender

                                      By: Signature Illegible
                                          ------------------------------------
                                          Name:_______________________________
                                          Title: Director
<PAGE>

                                        BAYERISCHE HYPO- UND VEREINSBANK AG, NEW
                                        YORK BRANCH, as a Lender

                                        By:_____________________________________
                                           Name:________________________________
                                           Title:_______________________________

                                        By:_____________________________________
                                           Name:________________________________
                                           Title:_______________________________
<PAGE>

                                    BEAR STEARNS CORPORATE LENDING INC., as a
                                    Lender

                                    By: Signature Illegible
                                        -----------------------------------
                                        Name:______________________________
                                        Title:_____________________________
<PAGE>

                                 CARAVELLE INVESTMENT FUND, L.L.C., as a Lender
                                 By: Caravelle Advisors L.L.C.

                                 By: /s/ Dean Criares
                                     -------------------------------------
                                     Name: Dean Criares
                                     Title: Managing Director
<PAGE>

                                   CENTURION CDO II, LTD., as a Lender
                                   By: American Express Asset Management Group,
                                   Inc., as Collateral Manager

                                   By: /s/ Steven B. Staver
                                       ----------------------------------
                                       Name: Steven B. Staver
                                       Title: Managing Director
<PAGE>

                                   CARLYLE HIGH YIELD PARTNER II, LTD., as a
                                   Lender

                                   By: /s/ Linda M. Pace
                                       -----------------------------------
                                       Name: Linda M. Pace
                                       Title: Vice President
<PAGE>

                                  CITIZENS BANK OF MASSACHUSETTS, as successor
                                  to US Trust, as a Lender

                                  By: /s/ Daniel G. Eastman
                                      ------------------------------------
                                      Name: Daniel G. Eastman
                                      Title: Senior Vice President
<PAGE>

                                   COBANK, ACB, as a Lender

                                   By: /s/ Anita Youngblut
                                       --------------------------------
                                       Name: Anita Youngblut
                                       Title: Vice President
<PAGE>

                         COOPERATIEVE CENTRALE RAIFFEISEN-BOERENLEENBANK B.A.,
                         "RABOBANK NEDERLAND", NEW YORK BRANCH

                         By: /s/ Michael R. Phelan
                             ------------------------------------------
                             Name: Michael R. Phelan
                             Title: Executive Director

                         By: /s/ W. Pieter Kedde
                             ------------------------------------------
                             Name: W. Pieter Kedde
                             Title: Managing Director
<PAGE>

                         THE CIT GROUP/EQUIPMENT FINANCING, INC., as a Lender

                         By:__________________________________________
                            Name:_____________________________________
                            Title:____________________________________
<PAGE>

                         CITICORP USA, INC., as a Lender

                         By: /s/ Suzanne Crymes
                             ------------------------------
                             Name:  Suzanne Crymes
                             Title: Vice President
<PAGE>

                         DEXIA PUBLIC FINANCE BANK-NEW YORK AGENCY (f/k/a CREDIT
                         LOCAL DE FRANCE - NEW YORK
                         AGENCY), as a Lender

                         By:__________________________________________
                            Name:_____________________________________
                            Title:____________________________________

                         By:__________________________________________
                            Name:_____________________________________
                            Title:____________________________________
<PAGE>

                         CREDIT LYONNAIS NEW YORK BRANCH, as a Lender

                         By: /s/ Patrick McCarthy
                             -------------------------------------
                            Name: Patrick McCarthy
                                  --------------------------------
                            Title: Authorized Signature
                                   -------------------------------
<PAGE>

                         CYPRESSTREE INVESTMENT MANAGEMENT COMPANY, INC., as a
                         Lender
                         As: Attorney-in-Fact and on behalf of First Allmerica
                         Financial Life Insurance Company as Portfolio Manager

                         By: Signature illegible
                             -----------------------------------------
                            Name:
                                  ------------------------------------
                            Title: Principal
                                   -----------------------------------

                         CYPRESSTREE INVESTMENT PARTNERS I, LTD., as a Lender
                         By:  CypressTree Investment Management Company, Inc.,
                         as Portfolio Manager

                         By: Signature illegible
                             -----------------------------------------
                            Name:
                                  ------------------------------------
                            Title: Principal
                                   -----------------------------------

                         CYPRESSTREE INVESTMENT PARTNERS II, LTD., as a Lender
                         By:  CypressTree Investment Management Company, Inc.,
                         as Portfolio Manager

                         By: Signature illegible
                             -----------------------------------------
                            Name:
                                  ------------------------------------
                            Title: Principal
                                   -----------------------------------

                         CYPRESSTREE SENIOR FLOATING RATE FUND, as a Lender
                         By: CypressTree Investment Management Company, Inc., as
                         Portfolio Manager

                         By: Signature illegible
                             -----------------------------------------
                            Name:
                                  ------------------------------------
                            Title: Principal
                                   -----------------------------------
<PAGE>

                         NORTH AMERICAN SENIOR FLOATING RATE FUND, as a Lender
                         By: CypressTree Investment Management Company, Inc., as
                         Portfolio Manager

                         By: Signature illegible
                             ----------------------------------
                             Name:
                             Title: Principal
<PAGE>

                         NIB CAPITAL BANK N.V., as a Lender

                         By: Signature illegible
                             -----------------------------------------
                             Name: ___________________________________
                             Title: __________________________________

                         By: Signature illegible
                             -----------------------------------------
                             Name:____________________________________
                             Title:___________________________________
<PAGE>

                         DRESDNER BANK AG, NEW YORK AND GRAND CAYMAN BRANCHES,
                         as a Lender

                         By: /s/ Patrick A. Keleher
                             -----------------------------------------
                             Name:  Patrick A. Keleher
                             Title: First Vice President

                         By: /s/ William E. Lambert
                             -----------------------------------------
                             Name:  William E. Lambert
                             Title: Vice President
<PAGE>

                         EATON VANCE CDO III, LTD., as a Lender
                         By:  Eaton Vance Management, as Investment Advisor

                         By: /s/ Payson F. Swaffield
                             -----------------------------------------
                             Name:  Payson F. Swaffield
                             Title: Vice President

                         EATON VANCE INSTITUTIONAL SENIOR LOAN FUND, as a Lender
                         By:  Eaton Vance Management, as Investment Advisor

                         By: /s/ Payson F. Swaffield
                             -----------------------------------------
                             Name:  Payson F. Swaffield
                             Title: Vice President

                         EATON VANCE SENIOR INCOME TRUST, as a Lender
                         By:  Eaton Vance Management, as Investment Advisor

                         By: /s/ Payson F. Swaffield
                             -----------------------------------------
                             Name:  Payson F. Swaffield
                             Title: Vice President

                         GRAYSON & CO., as a Lender
                         By:  Boston Management and Research, as Investment
                         Advisor

                         By: /s/ Payson F. Swaffield
                             -----------------------------------------
                             Name:  Payson F. Swaffield
                             Title: Vice President
<PAGE>

                         OXFORD STRATEGIC INCOME FUND, as a Lender
                         By:  Eaton Vance Management, as Investment Advisor

                         By: /s/ Payson F. Swaffield
                             ---------------------------------
                             Name: Payson F. Swaffield
                             Title: Vice President

                         SENIOR DEBT PORTFOLIO, as a Lender
                         By:  Boston Management and Research, as Investment
                         Advisor

                         By: /s/ Payson F. Swaffield
                             ---------------------------------
                             Name: Payson F. Swaffield
                             Title: Vice President
<PAGE>

                         ERSTE BANK DER OESTERREICHISCHEN SPARKASSEN AG, as a
                         Lender

                         By: /s/ John Fay
                             --------------------------------------
                             Name:  John Fay
                             Title: Vice President

                         By: /s/ John S. Bunnion
                             --------------------------------------
                             Name:  John S. Bunnion
                             Title: First Vice President
<PAGE>

                         FC-CBO II LIMITED, as a Lender

                         By: Signature illegible
                             ----------------------------------------
                             Name:  __________________________________
                             Title: Collateral Manager
<PAGE>

                         FIDELITY ADVISOR SERIES II: FIDELITY ADVISOR HIGH
                         INCOME FUND, as a Lender

                         By: Signature illegible
                             ------------------------------------------
                             Name: ____________________________________
                             Title: ___________________________________

                         VARIABLE INSURANCE PRODUCTS FUND II: ASSET MANAGER
                         PORTFOLIO, as a Lender

                         By: Signature illegible
                             ------------------------------------------
                             Name: ____________________________________
                             Title: ___________________________________

                         VARIABLE INSURANCE PRODUCTS FUND II: ASSET MANAGER
                         GROWTH PORTFOLIO, as a Lender

                         By: Signature illegible
                             ------------------------------------------
                             Name: ____________________________________
                             Title: ___________________________________
<PAGE>

                         FIRST DOMINION FUNDING III, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         FIRST UNION NATIONAL BANK, as a Lender

                         By: /s/ Bruce W. Loftin
                             ------------------------------------
                             Name:  Bruce W. Loftin
                             Title: Senior Vice President
<PAGE>

                         FLEET NATIONAL BANK, as a Lender

                         By: /s/ Ellery Willard
                             ---------------------------------
                             Name:  Ellery Willard
                             Title: Vice President
<PAGE>

                         FRANKLIN FLOATING RATE TRUST, as a Lender

                         By: /s/ Chauncey Lufkin
                             ------------------------------------
                             Name:  Chauncey Lufkin
                             Title: Vice President
<PAGE>

                         THE FUJI BANK, LIMITED, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         GALAXY CLO 1999-1, LTD., as a Lender
                         By: SAI Investment Adviser, Inc.,
                         its Collateral Agent

                         By: /s/ Thomas G. Brandt
                             ----------------------------------
                             Name:  Thomas G. Brandt
                             Title: Authorized Agent
<PAGE>

                         GENERAL ELECTRIC CAPITAL CORPORATION, as a Lender

                         By: /s/ Brian P. Ward
                             ---------------------------------------
                             Name:  Brian P. Ward
                             Title: Manager-Operations
<PAGE>

                         HOWARD BANK, N.A., as a Lender

                         By: /s/ Michael W. Quinn
                             -------------------------------------
                             Name:  Michael W. Quinn
                             Title: Jr. Vice President
<PAGE>

                         IBM CREDIT CORPORATION, as a Lender

                         By: /s/ Thomas S. Curcio
                             -----------------------------------
                            Name:  Thomas S. Curcio
                            Title: Manager of Credit, Commercial and
                                   Specialty Financing
<PAGE>

                         KEMPER FLOATING RATE FUND, as a Lender

                         By: /s/ Kelly D. Babson
                             ---------------------------------
                             Name:  Kelly D. Babson
                             Title: Managing Director
<PAGE>

                         KEY CORPORATE CAPITAL INC., as a Lender

                         By: /s/ Jason R. Weaver
                             ------------------------------------
                             Name:  Jason R. Weaver
                             Title: Senior Vice President
<PAGE>

                         KZH CYPRESSTREE-1 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH ING-1 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH ING-2 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH ING-3 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH LANGDALE LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         KZH RIVERSIDE LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH SHOSHONE LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH SOLEIL-2 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         LEHMAN COMMERCIAL PAPER INC., as a Lender

                         By: /s/ G. Andrew Keith
                             ---------------------------------
                             Name:  G. Andrew Keith
                             Title: Authorized Signatory
<PAGE>

                         MERRILL LYNCH GLOBAL INVESTMENT SERIES: INCOME
                         STRATEGIES PORTFOLIO, as a Lender
                         By: Merrill Lynch Investment Managers, L.P., as
                             Investment Advisor

                         By: /s/ Andrew C. Liggio
                             -------------------------------------
                             Name:  Andrew C. Liggio
                             Title: Authorized Signatory

                         MERRILL LYNCH PRIME RATE PORTFOLIO, as a Lender
                         By: Merrill Lynch Investment Managers, L.P., as
                             Investment Advisor

                         By: /s/ Andrew C. Liggio
                             -------------------------------------
                             Name:  Andrew C. Liggio
                             Title: Authorized Signatory

                         MASTER SENIOR FLOATING RATE TRUST, as a Lender

                         By: /s/ Andrew C. Liggio
                             -------------------------------------
                             Name:  Andrew C. Liggio
                             Title: Authorized Signatory

                         MERRILL LYNCH SENIOR FLOATING RATE FUND, INC., as a
                         Lender

                         By: /s/ Andrew C. Liggio
                             -------------------------------------
                             Name:  Andrew C. Liggio
                             Title: Authorized Signatory
<PAGE>

                         SENIOR HIGH INCOME PORTFOLIO, INC., as a Lender

                         By: /s/ Andrew C. Liggio
                             -------------------------------------
                             Name:  Andrew C. Liggio
                             Title: Authorized Signatory

                         DEBT STRATEGIES FUND, INC., as a Lender

                         By: /s/ Andrew C. Liggio
                             -------------------------------------
                             Name:  Andrew C. Liggio
                             Title: Authorized Signatory

                         LONGHORN CDO (CAYMAN) LTD., as a Lender
                         By: Merrill Lynch Asset Management, L.P., as Attorney
                         In Fact

                         By: /s/ Andrew C. Liggio
                             -------------------------------------
                             Name:  Andrew C. Liggio
                             Title: Authorized Signatory
<PAGE>

                         METROPOLITAN LIFE INSURANCE COMPANY, as a Lender

                         By: /s/ Erik V. Savi
                             ------------------------------------
                             Name:  Erik V. Savi
                             Title: Director
<PAGE>

                         THE MITSUBISHI TRUST AND BANKING CORPORATION, as a
                         Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         MONY LIFE INSURANCE COMPANY, as a Lender

                         By: /s/ Emilia F. Wiener
                             -------------------------------------
                             Name:  Emilia F. Wiener
                             Title: Managing Director
<PAGE>

                              MORGAN STANLEY DEAN WITTER PRIME INCOME
                              TRUST, as a Lender

                              By: /s/ Sheila Finnerty
                                  ----------------------------------
                                  Name:  Sheila Finnerty
                                  Title: Senior Vice President
<PAGE>

                              MOUNTAIN CAPITAL CLO I, LTD., as a Lender

                              By:________________________________________
                                 Name:___________________________________
                                 Title:__________________________________
<PAGE>

                              MUIRFIELD TRADING LLC, as a Lender

                              By: /s/ Ann E. Morris
                                  ----------------------------------
                                  Name:  Ann E. Morris
                                  Title: Senior Vice President

                              OLYMPIC FUNDING TRUST, SERIES 1999-1, as a
                              Lender

                              By: /s/ Ann E. Morris
                                  ----------------------------------
                                  Name:  Ann E. Morris
                                  Title: Senior Vice President

                              PPM SPYGLASS FUNDING TRUST, as a Lender

                              By: /s/ Ann E. Morris
                                  ----------------------------------
                                  Name:  Ann E. Morris
                                  Title: Senior Vice President

                              WINGED FOOT FUNDING TRUST, as a Lender

                              By: /s/ Ann E. Morris
                                  ----------------------------------
                                  Name:  Ann E. Morris
                                  Title: Senior Vice President
<PAGE>

                              NATEXIS BANQUES POPULAIRES, as a Lender

                              By: /s/ Cynthia E. Sachs
                                  ------------------------------------
                                  Name:  Cynthia E. Sachs
                                  Title: N.P. Group Manager

                              By: /s/ Elizabeth A. Harker
                                  ------------------------------------
                                  Name:  Elizabeth A. Harker
                                  Title: Assistant Vice President
<PAGE>

                              NATIONAL CITY BANK, as a Lender

                              By:   /s/ Jon W. Peterson
                                 -------------------------------
                                 Name:   Jon W. Peterson
                                      --------------------------
                                 Title:  Senior Vice President
                                      --------------------------
<PAGE>

                         OCTAGON INVESTMENT PARTNERS II, LLC, as a Lender
                         By: Octagon Credit Investors, LLC, as sub-investment
                         manager

                         By:    /s/ Andrew D. Gordon
                            -------------------------------------
                            Name:   Andrew D. Gordon
                                 --------------------------------
                            Title:  Portfolio Manager
                                 --------------------------------

                         OCTAGON INVESTMENT PARTNERS III, LTD., as a Lender
                         By: Octagon Credit Investors, LLC, as Portfolio
                         Manager

                         By:    /s/ Andrew D. Gordon
                            -------------------------------------
                            Name:   Andrew D. Gordon
                                 --------------------------------
                            Title:  Portfolio Manager
                                 --------------------------------
<PAGE>

                         OPPENHEIMER SENIOR FLOATING RATE FUND, as a Lender

                         By:    /s/ David Farhoven
                            --------------------------------
                            Name:   David Farhoven
                                 ---------------------------
                            Title:  A.V.P.
                                 ---------------------------
<PAGE>

                         ING PILGRIM SENIOR INCOME FUND, as a Lender
                         By: ING Pilgrim Investments, Inc., as its investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         ML CLO XV PILGRIM AMERICA (CAYMAN) LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:__________________________________________________
                            Name:_____________________________________________
                            Title:____________________________________________

                         ML CLO XX PILGRIM AMERICA (CAYMAN) LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:__________________________________________________
                            Name:_____________________________________________
                            Title:____________________________________________

                         PILGRIM CLO 1999-1 LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:__________________________________________________
                            Name:_____________________________________________
                            Title:____________________________________________

<PAGE>

                         PILGRIM PRIME RATE TRUST, as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:__________________________________________________
                            Name:_____________________________________________
                            Title:____________________________________________

                         SEQUILS-PILGRIM 1, LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:__________________________________________________
                            Name:_____________________________________________
                            Title:____________________________________________
<PAGE>

                         PNC BANK, NATIONAL ASSOCIATION, as a Lender

                         By:   /s/ Keith R. White
                            ---------------------------------
                            Name:   Keith R. White
                                 ----------------------------
                            Title:  Vice President
                                 ----------------------------
<PAGE>

                           PUTNAM HIGH YIELD TRUST, as a Lender

                         By:    /s/ John R. Verani
                            ------------------------------
                            Name:   John R. Verani
                                 -------------------------
                            Title:  Vice President
                                 -------------------------
<PAGE>

                                   ROYAL BANK OF CANADA, as a Lender

                                   By:    /s/ John M. Crawford
                                      -----------------------------
                                      Name:   John M. Crawford
                                           ------------------------
                                      Title:
                                           ------------------------
<PAGE>

                                   SANKATY HIGH YIELD PARTNERS II, L.P., as a
                                   Lender under the Loan Agreement

                                   By:    /s/ Diane J. Exter
                                      --------------------------------
                                      Name:   Diane J. Exter
                                           ---------------------------
                                      Title:  Portfolio Manager
                                           ---------------------------

                                   Sankaty Advisors, Inc. as Collateral Manager
                                   for GREAT POINT CLO 1999-1 LTD., as Term
                                   Lender and as a Lender under the Loan
                                   Agreement

                                   By:    /s/ Diane J. Exter
                                      --------------------------------
                                      Name:   Diane J. Exter
                                           ---------------------------
                                      Title:  Portfolio Manager
                                           ---------------------------
<PAGE>

                                   SEABOARD CLO 2000 LTD, as a Lender

                                   By:_______________________________________
                                      Name:__________________________________
                                      Title:_________________________________
<PAGE>

                                   SENECA CBO II, L.P., as a Lender

                                   By:     /s/ Janice Diamond
                                      -------------------------------
                                      Name:   Janice Diamond
                                           --------------------------
                                      Title:  Partner
                                           --------------------------

                                   SENECA CBO III, LIMITED, as a Lender

                                   By:     /s/ Janice Diamond
                                      -------------------------------
                                      Name:   Janice Diamond
                                           --------------------------
                                      Title:  Partner
                                           --------------------------
<PAGE>

                                   SEQUILS-CUMBERLAND I, LTD., as a Lender
                                   By: Deerfield Capital Management, L.L.C., as
                                   its Collateral Manager

                                   By:    /s/ Mark E. Wittnebel
                                      ----------------------------------
                                      Name:   Mark E. Wittnebel
                                           -----------------------------
                                      Title:  Senior Vice President
                                           -----------------------------
<PAGE>

                                   SUNTRUST BANK, as a Lender

                                   By: Signature Illegible
                                      --------------------------------
                                      Name:
                                           ---------------------------
                                      Title:
                                           ---------------------------
<PAGE>

                                   TEXTRON FINANCIAL CORPORATION, as a Lender

                                   By: /s/ Matthew J. Colgan
                                       -----------------------------------
                                       Name: Matthew J. Colgan
                                       Title: Director
<PAGE>

                                   UNION BANK OF CALIFORNIA, N.A., as a Lender

                                   By: Signature Illegible
                                       ---------------------------------------
                                       Name:__________________________________
                                       Title:_________________________________
<PAGE>

                                   VAN KAMPEN CLO I, LIMITED, as a Lender
                                   By: Van Kampen Management, Inc., as
                                   Collateral Manager

                                   By: /s/ Darvin D. Pierce
                                       ----------------------------------
                                       Name: Darvin D. Pierce
                                       Title: Principal

                                   VAN KAMPEN CLO II, LIMITED, as a Lender
                                   By: Van Kampen Management, Inc., as
                                   Collateral Manager

                                   By: /s/ Darvin D. Pierce
                                       ----------------------------------
                                       Name: Darvin D. Pierce
                                       Title: Principal

                                   VAN KAMPEN SENIOR INCOME TRUST, as a Lender
                                   By: Van Kampen Investment Advisory Corp.

                                   By: /s/ Darvin D. Pierce
                                       ----------------------------------
                                       Name: Darvin D. Pierce
                                       Title: Principal

<PAGE>

                                   WEBSTER BANK, as a Lender

                                   By: /s/ Matthew Daly
                                       -------------------------------------
                                       Name: Matthew Daly
                                       Title: AVP<PAGE>

                                                                    Exhibit 10.6

                          FIFTH AMENDMENT AND WAIVER
                                      TO
                      AMENDED AND RESTATED LOAN AGREEMENT

     THIS FIFTH AMENDMENT AND WAIVER TO AMENDED AND RESTATED LOAN AGREEMENT,
dated as of the 26th day of March, 2001 (this "Amendment"), is made by and among
                                               ---------
AMERICAN TOWER, L.P., a Delaware limited partnership, AMERICAN TOWERS, INC., a
Delaware corporation, VERESTAR, INC. (f/k/a ATC TELEPORTS, INC.), a Delaware
corporation (collectively, the "Borrowers"), THE FINANCIAL INSTITUTIONS
                                ---------
SIGNATORIES HERETO and TORONTO DOMINION (TEXAS), INC., as administrative agent
(in such capacity, the "Administrative Agent").
                        --------------------

                             W I T N E S S E T H:
                             - - - - - - - - - -

     WHEREAS, the Borrowers, the Lenders (as defined therein), the Issuing Bank
(as defined therein) and the Administrative Agent are all parties to that
certain Amended and Restated Loan Agreement dated as of January 6, 2000 (as
previously amended and as hereafter amended, modified, restated and supplemented
from time to time, the "Loan Agreement"); and
                        --------------

     WHEREAS, the Borrowers have requested amendments to certain provisions of
the Loan Agreement, and, subject to the terms and conditions set forth herein,
the Lenders and the Administrative Agent are willing to amend certain provisions
of the Loan Agreement as more specifically set forth herein;

     NOW, THEREFORE, in consideration of the premises set forth above, and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree that all capitalized terms used
and not defined herein shall have the meanings ascribed to such terms in the
Loan Agreement, and further hereby agree as follows:

     1.   Amendments. The Loan Agreement is hereby amended as more fully set for
          ----------
the below:

          (a)    Amendments to Article 1.
                 -----------------------

                 (i)     Section 1.1 of the Loan Agreement, Definitions, is
                                                            -----------
     hereby amended by deleting the definitions of "Available Revolving Loan
                                                    ------------------------
     Commitment" and "Borrowers" in their entirety and by substituting the
     ----------       ---------
     following definitions in lieu thereof:

          "'Available Revolving Loan Commitment'" shall mean, as of any date,
            -----------------------------------
     (a) for all times prior to the Borrowing Base Termination Date, the lesser
     of (i)(A) the Revolving Loan Commitments in effect on such date minus (B)
                                                                     -----
     the sum of (1) the Revolving Loans then outstanding plus (2) the Letter of
                                                         ----
     Credit Obligations then outstanding, and (ii)(A) the Borrowing Base on such
                                          ---
     date minus (B) the sum of (1) all Loans then outstanding plus (2) the
          -----                                               ----
     Letter of Credit Obligations then outstanding plus (3) any Capitalized
                                                   ----
     Lease Obligations then outstanding, and, (b) for all other times, the
     difference between (i) the
<PAGE>

     Revolving Loan Commitments in effect on such date minus (ii) the sum of (A)
                                                       -----
     the Revolving Loans then outstanding plus (B) the Letter of Credit
                                          ----
     Obligations then outstanding."

          "'Borrowers' shall mean, collectively, AT L.P., AT Inc., Verestar,
            ---------
     Inc. (f/k/a ATC Teleports), and Towersites Monitoring, Inc., a Delaware
     corporation, and shall include Kline Steel and such other Persons as may be
     approved by the Majority Lenders at such time as any such Person executes
     and delivers to the Administrative Agent an assignment and assumption
     agreement in form and substance satisfactory to the Administrative Agent
     and each other Loan Document as executed by the other Borrowers; and
     "Borrower" shall mean any one of the foregoing."
      --------

                 (ii)    Section 1.1 of the Loan Agreement, Definitions, is
                                                            -----------
     hereby further amended by deleting the reference to Section 7.6(d) in the
     definition of "Loan Purchase Agreement" and replacing it with Section
                    -----------------------
     7.6(b).

                 (iii)   Section 1.1 of the Loan Agreement, Definitions, is
                                                            -----------
hereby further amended by inserting the following new definitions of "ATC
                                                                      ---
International", "ATC Mexico", and "Net Investment Amount" in the proper
-------------    ----------        ---------------------
alphabetical order:

          "'ATC International' shall mean ATC International Holdings Corp., a
            -----------------
     Delaware corporation, and any entity that is a successor thereto."

          "'ATC Mexico' shall mean American Tower Corporation de Mexico, S. de
            ----------
     R.L. de C.V., a Mexico limited liability company, and any entity that is a
     successor thereto."

          "'Net Investment Amount' shall mean an amount equal to the excess of
            ---------------------
     (a) the aggregate amount (valued, for these purposes, at their original
     cost) of all such Investments (which, for these purposes shall not include
     the distribution by AT Inc. of its Investment in ATC Mexico to ATC
     International) made pursuant to the provisions of Section 7.6(b) hereof
     from and after March 31, 2001, over (b) the sum of (i) the net cash
     proceeds received upon sale, transfer or other disposition of any such
     Investments, or any Investments derived therefrom (after deducting costs
     and expenses of sale, transfer or other disposition), and (ii) the
     aggregate amount of such Investments made pursuant to Section 7.6(b)(iii)
     hereof in Persons whose acquisition, merger or lease/sublease agreement
     with the Parent, any Borrower or any of the Restricted Subsidiaries shall
     have been consummated (so long as the assets acquired or leased are owned
     or leased by any Borrower or any of the Restricted Subsidiaries)."

          (b)    Amendment to Article 2. Section 2.7(b)(vi) of the Loan
                 ----------------------
     Agreement Loans in excess of Borrowing Base, is hereby amended by deleting
               ---------------------------------
     such section in its entirety and substituting in lieu thereof the following
     section:

                 "(vi)   Loans in Excess of Borrowing Base. If, on any date
                         ---------------------------------
     prior to the Borrowing Base Termination Date, the Loans then outstanding
     exceed the difference of

                                     - 2 -
<PAGE>

     (A) the Borrowing Base minus (B) any Capitalized Lease Obligations then
                            -----
     outstanding on such date, the Loans shall be repaid in an amount equal to,
     in the aggregate, such excess. The Borrowers may, at their option, apply
     such reduction to the Revolving Loans, the Term Loan A Loans or Term Loan B
     Loans."

          (c)    Amendment to Article 7.
                 ----------------------

          (i)    Section 7.1 of the Loan Agreement, Indebtedness of the
                                                    -------------------
     Borrowers and the Restricted Subsidiaries, is hereby amended by deleting
     -----------------------------------------
     subsection (g) thereof in its entirety and substituting in lieu thereof the
     following:

                 "(g)  Capitalized Lease Obligations;"

          (ii)   Section 7.6 of the Loan Agreement, Investments and
                                                    ---------------
     Acquisitions, is hereby amended by deleting subsection (b) thereof in its
     ------------
     entirety and substituting in lieu thereof the following:

                 "(b)    so long as no Default then exists or would be caused
          thereby, establish Unrestricted Subsidiaries and make Investments in
          (i) such Unrestricted Subsidiaries (in addition to Investments
          permitted under Section 7.6(e), (f) and (g) hereof), (ii) ATC
          International and (iii) Persons primarily engaged in domestic and
          foreign communications tower and tower related businesses in an
          aggregate amount, directly or indirectly (including notwithstanding
          anything in this Loan Agreement to the contrary, distributions to the
          Parent that are contemporaneously contributed as equity or loaned (if
          such loan is evidenced by a note) to ATC International, which
          distributions shall not be deemed Restricted Payments for the purposes
          of this Agreement), provided that, giving effect to such additional
          Investment, the aggregate Net Investment Amount made pursuant to the
          provisions of this Section 7.6(b) from and after March 31, 2001 shall
          not exceed (x) $350,000,000.00 if at the time of such Investment the
          Leverage Ratio is greater than or equal to 6.00 to 1.00 and (y)
          $500,000,000.00 at all other times; provided that, in the case of
                                              --------
          Investments made pursuant to clause (ii) of this Section 7.6(b), the
          Parent grants to the Lenders a first priority security interest in the
          Parent's ownership thereof and any notes executed in connection
          therewith and ATC International executes a Guaranty in favor of the
          Lenders; and provided further that, in the case of Investments made
                       -------- -------
          pursuant to clause (iii) of this Section 7.6(b), the Parent, any
          Borrower or any of the Restricted Subsidiaries has executed a binding
          acquisition, merger, lease/sublease or management agreement with such
          Person;"

          (iii)  Section 7.6 of the Loan Agreement, Investments and
                                                    ---------------
     Acquisitions, is hereby further amended by deleting subsection (d) thereof
     -------------
     in its entirety and substituting in lieu thereof the following:

                 "(d)  [Reserved]"

                                     - 3 -
<PAGE>

     2.   Amendment to Schedule 2, Acknowledgment and Consent. The Borrowers
          ---------------------------------------------------
sent a notice (the "Notice") to the Lenders on February 23, 2001 designating
                    ------
American Tower Corporation de Mexico, S. de R.L. de C.V. ("ATC Mexico") as an
                                                           ----------
Unrestricted Subsidiary. To clarify the status of the Borrower's Subsidiaries,
Schedule 2 to the Loan Agreement, Restricted Subsidiaries and Unrestricted
----------
Subsidiaries, is hereby amended by deleting such schedule in its entirety and
substituting in lieu thereof Schedule 2 attached hereto. The Lenders also
                             ----------
consent to (a) the transfer of the equity interest in ATC Mexico to ATC
International Holdings Corp. ("ATC International"), a Delaware corporation,
                               -----------------
which transfer may be done by a distribution to the Parent that is then
contemporaneously transferred to ATC International (such distribution shall not
be deemed a Restricted Payment for purposes under the Agreement) and (b) that
prior to the transfer to ATC International, the equity of ATC Mexico held by AT
Inc. will not be pledged to the Lenders; provided, that if such transfer does
                                         --------
not occur within 180 days from the date hereof, the Borrowers shall grant to the
Lenders a first priority security interest on the equity on ATC Mexico (which
may be accomplished directly or indirectly through a domestic unrestricted
subsidiary holding company).

     3.   Waiver. The Borrowers have informed the Administrative Agent that they
          ------
were not in compliance with Section 7.1(g), Indebtedness of the Borrower and the
                                            ------------------------------------
Restricted Subsidiaries, as it related to Capitalized Lease Obligations as of
-----------------------
December 31, 2000. The Lenders hereby waive any Default or Event of Default that
may have occurred under Section 7.1(g) solely with respect to the Borrowers'
incurring Capitalized Lease Obligations in excess of $100,000,000 as of December
31, 2000 and through the date of this Amendment.

     4.   No Other Amendment or Waiver. Except for the amendments and waiver set
          ----------------------------
forth above, the text of the Loan Agreement and all other Loan Documents shall
remain unchanged and in full force and effect. No amendment or waiver by the
Administrative Agent, the Issuing Bank or the Lenders under the Loan Agreement
or any other Loan Document is granted or intended except as expressly set forth
herein, and the Administrative Agent, the Issuing Bank and the Lenders expressly
reserve the right to require strict compliance in all other respects (whether or
not in connection with any Requests for Advance). Except as set forth herein,
the amendments and waiver agreed to herein shall not constitute a modification
of the Loan Agreement or any of the other Loan Documents, or a course of dealing
with the Administrative Agent, the Issuing Bank and the Lenders at variance with
the Loan Agreement or any of the other Loan Documents, such as to require
further notice by the Administrative Agent, the Issuing Bank, the Lenders or the
Majority Lenders to require strict compliance with the terms of the Loan
Agreement and the other Loan Documents in the future.

     5.   Conditions Precedent. The effectiveness of this Amendment is subject
          --------------------
to the following:

     (a)  Receipt by the Administrative Agent of:

          (i)    duly executed signature pages to this Amendment from the
          Majority Lenders;

                                     - 4 -
<PAGE>

          (ii)   a duly executed Guaranty from ATC International Holdings Corp.

          (iii)  a duly executed Guaranty from Towersites Monitoring, Inc.

          (iv)   a duly executed Security Agreement from Towersites Monitoring,
          Inc.

          (v)    a duly executed Assumption Agreement, in form and substance
          acceptable to the Administrative Agent, from Towersites Monitoring,
          Inc.

          (vi)   a legal opinion from Sullivan & Worcester LLP, counsel to the
          Borrowers, its Subsidiaries and ATC International Holdings Corp. in
          form and substance addressed to the Administrative Agent and the
          Lenders and dated the date hereof;

          (vii)  a loan certificate of Towersites Monitoring, Inc., in
          substantially in the form of Exhibit V attached to the Loan Agreement,
          with all exhibits thereto; and

          (viii) UCC-1 financing statements signed by Towersites Monitoring,
          Inc. to be filed in the appropriate filing offices.

     (b)  The representations and warranties contained in Article 4 of the Loan
Agreement and contained in the other Loan Documents remain true and correct as
of the date hereof, both before and after giving effect to this Agreement,
except to the extent previously fulfilled in accordance with the terms of the
Loan Agreement or such other Loan Document, as applicable, or to the extent
relating specifically to the earlier date. No Default or Event of Default now
exists or will be caused hereby.

     6.   Counterparts. This Amendment may be executed in any number of
          ------------
counterparts, each of which shall be deemed to be an original, but all such
separate counterparts shall together constitute but one and the same instrument.

     7.   Governing Law. This Amendment shall be construed in accordance with
          -------------
and governed by the laws of the State of New York.

     8.   Severability. Any provision of this Amendment which is prohibited or
          ------------
unenforceable shall be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining provisions hereof in that
jurisdiction or affecting the validity or enforceability of such provision in
any other jurisdiction.

                 [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                     - 5 -
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Amendment or
caused it to be executed by their duly authorized officers, all as of the day
and year first above written.

BORROWERS:                         AMERICAN TOWER, L.P., a Delaware limited
                                   partnership

                                   By ATC GP INC., its General Partner

                                   By: /s/ Joseph L. Winn
                                      -----------------------------------
                                      Name: Joseph L. Winn
                                      Title: Chief Financial Officer

                                   AMERICAN TOWERS, INC., a Delaware corporation

                                   By: /s/ Joseph L. Winn
                                      -----------------------------------
                                      Name: Joseph L. Winn
                                      Title: Chief Financial Officer

                                   VERESTAR, INC., a Delaware corporation

                                   By: /s/ Joseph L. Winn
                                      -----------------------------------
                                      Name: Joseph L. Winn
                                      Title: Chief Financial Officer

                                   TOWERSITES MONITORING, INC., a Delaware
                                   corporation

                                   By: /s/ Joseph L. Winn
                                      -----------------------------------
                                      Name: Joseph L. Winn
                                      Title: Chief Financial Officer

<PAGE>

ADMINISTRATIVE AGENT
AND LENDERS:                       TORONTO DOMINION (TEXAS), INC., as
                                   Administrative Agent and as a Lender

                                   By:       /s/
                                      ------------------------------------
                                      Name: Jano Mott
                                      Title: Vice President
<PAGE>

                                   THE BANK OF NEW YORK, as a Lender

                                   By:       /s/
                                      ------------------------------------
                                      Name: Geoffrey C. Brooks
                                      Title: Senior Vice President
<PAGE>

                                   THE CHASE MANHATTAN BANK, as a Lender

                                   By:       /s/
                                      ------------------------------------
                                      Name: William E. Rottino
                                      Title: Vice President
<PAGE>

                                   CREDIT SUISSE FIRST BOSTON, as Lender

                                   By:       /s/
                                      ------------------------------------
                                      Name: David L. Sawyer
                                      Title: Vice President

                                   By:       /s/
                                      ------------------------------------
                                      Name: Lalita Advani
                                      Title:  Assistant Vice President
<PAGE>

                                   ALLFIRST BANK, as a Lender

                                   By:       /s/
                                      ------------------------------------
                                      Name: W. Blake Hampson
                                      Title: Vice President
<PAGE>

                                    ALLSTATE LIFE INSURANCE COMPANY, as a Lender

                                    By:_________________________________________
                                       Name:____________________________________
                                       Title:___________________________________

                                    By:_________________________________________
                                       Name:____________________________________
                                       Title:___________________________________

                                    AIMCO CDO SERIES 2000-A, as a Lender

                                    By:_________________________________________
                                       Name:____________________________________
                                       Title:___________________________________

                                    By:_________________________________________
                                       Name:____________________________________
                                       Title:___________________________________
<PAGE>

                             AMARA-2 FINANCE, LTD., as a Lender
                             By: INVESCO Senior Secured Management, Inc., as
                                 Subadvisor

                             By: /s/ Thomas H.B. Ewald
                                ------------------------------------------------
                                Name: Thomas H.B. Ewald
                                Title: Authorized Signatory

                             AVALON CAPITAL LTD., as a Lender
                             By: INVESCO Senior Secured Management, Inc., as
                                 Portfolio Advisor

                             By: /s/ Thomas H.B. Ewald
                                ------------------------------------------------
                                Name: Thomas H.B. Ewald
                                Title: Authorized Signatory

                             AVALON CAPITAL LTD. 2, as a Lender
                             By: INVESCO Senior Secured Management, Inc., as
                                 Portfolio Advisor

                             By: /s/ Thomas H.B. Ewald
                                ------------------------------------------------
                                Name: Thomas H.B. Ewald
                                Title: Authorized Signatory

                             CERES II FINANCE LTD., as a Lender
                             By: INVESCO Senior Secured Management, Inc., as
                                 Sub-Managing Agent (Financial)

                             By: /s/ Thomas H.B. Ewald
                                ------------------------------------------------
                                Name: Thomas H.B. Ewald
                                Title: Authorized Signatory
<PAGE>

                             CHARTER VIEW PORTFOLIO, as a Lender
                             By: INVESCO Senior Secured Management, Inc., as
                                 Investment Advisor

                             By: /s/ Thomas H.B. Ewald
                                ------------------------------------------------
                                Name: Thomas H.B. Ewald
                                Title: Authorized Signatory

                             TRITON CDO IV, LIMITED, as a Lender
                             By: INVESCO Senior Secured Management, Inc., as
                                 Investment Advisor

                             By: /s/ Thomas H.B. Ewald
                                ------------------------------------------------
                                Name: Thomas H.B. Ewald
                                Title: Authorized Signatory
<PAGE>

                             ARCHIMEDES FUNDING, L.L.C., as a Lender
                             By: ING Capital Advisors LLC, as Collateral Manager

                             By:________________________________________________
                                Name:___________________________________________
                                Title:__________________________________________

                             ARCHIMEDES FUNDING II, LTD., as a Lender
                             By: ING Capital Advisors LLC, as Collateral Manager

                             By:________________________________________________
                                Name:___________________________________________
                                Title:__________________________________________

                             ARCHIMEDES FUNDING III, LTD., as a Lender
                             By: ING Capital Advisors LLC, as Collateral Manager

                             By:________________________________________________
                                Name:___________________________________________
                                Title:__________________________________________

                             ARCHIMEDES FUNDING IV (CAYMAN), LTD., as a Lender
                             By: ING Capital Advisors LLC, as Collateral Manager

                             By:________________________________________________
                                Name:___________________________________________
                                Title:__________________________________________

                             SEQUILS-ING I (HBDGM), LTD., as Assignee
                             By: ING Capital Advisors LLC, as Collateral Manager

                             By:________________________________________________
                                Name:___________________________________________
                                Title:__________________________________________
<PAGE>

                         ADDISON CDO, LIMITED, as a Lender
                         By: Pacific Investment Management Company, LLC, as its
                             Investment Advisor

                         By: /s/ Mohan V. Phansalkar
                            ----------------------------------------------------
                            Name: Mohan V. Phansalkar
                            Title: Executive Vice President

                         ATHENA CDO, LIMITED, as a Lender
                         By: Pacific Investment Management Company, LLC, as its
                             Investment Advisor

                         By: /s/ Mohan V. Phansalkar
                            ----------------------------------------------------
                            Name: Mohan V. Phansalkar
                            Title: Executive Vice President

                         BEDFORD CDO, LIMITED, as a Lender
                         By: Pacific Investment Management Company, LLC, as its
                             Investment Advisor

                         By: /s/ Mohan V. Phansalkar
                            ----------------------------------------------------
                            Name: Mohan V. Phansalkar
                            Title: Executive Vice President

                         CAPTIVA III FINANCE LTD., as a Lender
                         As advised by Pacific Investment Management Company,
                         LLC

                         By: /s/ David Dyer
                            ----------------------------------------------------
                            Name: David Dyer
                            Title: Director
<PAGE>

                         CAPTIVA IV FINANCE LTD., as a Lender
                         As advised by Pacific Investment Management Company,
                         LLC

                         By: /s/ David Dyer
                            ----------------------------------------------------
                            Name: David Dyer
                            Title: Director
<PAGE>

                         DELANO COMPANY, as a Lender
                         By: Pacific Investment Management Company, LLC, as its
                             Investment Advisor

                         By: /s/ Mohan V. Phansalkar
                            ----------------------------------------------------
                            Name: Mohan V. Phansalkar
                            Title: Executive Vice President

                         JISSEKIKUN FUNDING, LTD., as a Lender
                         By: Pacific Investment Management Company, LLC, as its
                             Investment Advisor

                         By: /s/ Mohan V. Phansalkar
                            ----------------------------------------------------
                            Name: Mohan V. Phansalkar
                            Title: Executive Vice President

                         ROYALTON COMPANY, as a Lender
                         By: Pacific Investment Management Company, LLC, as its
                             Investment Advisor

                         By: /s/ Mohan V. Phansalkar
                            ----------------------------------------------------
                            Name: Mohan V. Phansalkar
                            Title: Executive Vice President
<PAGE>

                                  BALANCED HIGH YIELD FUND I LTD., as a Lender
                                  By: BHF (USA) Capital Corporation
                                      Acting as Attorney-in-Fact

                                  By:___________________________________________
                                     Name:______________________________________
                                     Title:_____________________________________

                                  By:___________________________________________
                                     Name:______________________________________
                                     Title:_____________________________________

                                  BALANCED HIGH YIELD FUND II, LTD., as a Lender
                                  By: BHF (USA) Capital Corporation
                                      Acting as Attorney-in-Fact

                                  By:___________________________________________
                                     Name:______________________________________
                                     Title:_____________________________________

                                  By:___________________________________________
                                     Name:______________________________________
                                     Title:_____________________________________
<PAGE>

                                  BANK OF AMERICA, N.A., as a Lender

                                  By:___________________________________________
                                     Name:______________________________________
                                     Title:_____________________________________

<PAGE>

                                   BANK OF MONTREAL, as a Lender

                                   By: /s/ Sarah Kim
                                      ------------------------------------------
                                      Name: Sarah Kim
                                      Title: Director

<PAGE>

                                    THE BANK OF NOVA SCOTIA, as a Lender

                                    By: /s/ P.A. Weissenberger
                                       -----------------------------------------
                                       Name: P.A. Weissenberger
                                       Title: Authorized Signatory
<PAGE>

                         BANK OF SCOTLAND, as a Lender

                         By:______________________________________
                            Name:_________________________________
                            Title:________________________________
<PAGE>

                         BANK UNITED, as a Lender

                         By:___________________________________________
                            Name:______________________________________
                            Title:_____________________________________
<PAGE>

                         BANKERS TRUST COMPANY, as a Lender

                         By:____________________________________________
                            Name:_______________________________________
                            Title:______________________________________
<PAGE>

                         BAYERISCHE HYPO- UND VEREINSBANK AG, NEW
                         YORK BRANCH, as a Lender

                         By:____________________________________________
                            Name:_______________________________________
                            Title:______________________________________

                         By:____________________________________________
                            Name:_______________________________________
                            Title:______________________________________
<PAGE>

                         BEAR STEARNS CORPORATE LENDING INC., as a
                         Lender

                         By:          /s/
                            ---------------------------------------------
                            Name: Victor F. Bulzacchelli
                            Title: Managing Director
<PAGE>

                         CARAVELLE INVESTMENT FUND, L.L.C., as a Lender
                         By:Caravelle Advisors L.L.C.

                         By:________________________________________________
                            Name:___________________________________________
                            Title:__________________________________________
<PAGE>

                         CENTURION CDO II, LTD., as a Lender
                         By:American Express Asset Management Group, Inc., as
                         Collateral Manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         CARLYLE HIGH YIELD PARTNER II, LTD., as a
                         Lender

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________

                         CARLYLE HIGH YIELD PARTNER III, LTD., as a
                         Lender

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________
<PAGE>

                         CITIZENS BANK OF MASSACHUSETTS, as successor
                         to US Trust, as a Lender

                         By:          /s/
                            ------------------------------------------------
                            Name:  Daniel G. Eastman
                            Title:  Senior Vice President
<PAGE>

                         COBANK, ACB, as a Lender

                         By:____________________________________________
                            Name:_______________________________________
                            Title:______________________________________
<PAGE>

                         CONTINENTAL CASUALTY COMPANY, as a Lender

                         By:          /s/
                            ------------------------------------------
                            Name: Richard W. Dubberke
                            Title: Vice President
<PAGE>

                         COOPERATIEVE CENTRALE RAIFFEISEN-BOERENLEENBANK B.A.,
                         "RABOBANK NEDERLAND", NEW YORK BRANCH, as a Lender

                         By:          /s/
                            ------------------------------------------------
                            Name:  Douglas W. Zylstra
                            Title: Senior Vice President

                         By:          /s/
                            -------------------------------------------------
                            Name:  James S> Cunningham
                            Title: Managing Director, Chief Risk Officer
<PAGE>

                         THE CIT GROUP/EQUIPMENT FINANCING, INC., as a Lender

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________
<PAGE>

                         DEXIA PUBLIC FINANCE BANK-NEW YORK AGENCY (f/k/a CREDIT
                         LOCAL DE FRANCE - NEW YORK AGENCY), as a Lender

                         By:__________________________________________________
                            Name:_____________________________________________
                            Title:____________________________________________

                         By:__________________________________________________
                            Name:_____________________________________________
                            Title:____________________________________________
<PAGE>

                         CREDIT LYONNAIS NEW YORK BRANCH, as a Lender

                         By:            /s/
                            -----------------------------------------
                            Name:  Patrick McCarthy
                            Title: Authorized Signatory
<PAGE>

                         CYPRESSTREE INVESTMENT MANAGEMENT COMPANY, INC., as a
                         Lender
                         As: Attorney-in-Fact and on behalf of First Allmerica
                         Financial Life Insurance Company as Portfolio Manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         CYPRESSTREE INVESTMENT PARTNERS I, LTD., as a Lender
                         By: CypressTree Investment Management Company, Inc.,
                         as Portfolio Manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         CYPRESSTREE INVESTMENT PARTNERS II, LTD., as a Lender
                         By: CypressTree Investment Management Company, Inc.,
                         as Portfolio Manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         CYPRESSTREE SENIOR FLOATING RATE FUND, as a Lender
                         By: CypressTree Investment Management Company, Inc., as
                         Portfolio Manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

<PAGE>

                         NORTH AMERICAN SENIOR FLOATING RATE FUND, as a Lender
                         By: CypressTree Investment Management Company, Inc., as
                         Portfolio Manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         NIB CAPITAL BANK N.V., as a Lender

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________
<PAGE>

                         DRESDNER BANK AG, NEW YORK AND GRAND CAYMAN BRANCHES,
                         as a Lender

                         By:           /s/
                            ---------------------------------------------
                            Name:  Patrick A. Keleher
                            Title: First Vice President

                         By:           /s/
                            ----------------------------------------------
                            Name:  Brian Schneider
                            Title: Assistant Vice President
<PAGE>

                         EATON VANCE CDO III, LTD., as a Lender
                         By: Eaton Vance Management, as Investment Advisor

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         EATON VANCE INSTITUTIONAL SENIOR LOAN FUND, as a Lender
                         By: Eaton Vance Management, as Investment Advisor

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         EATON VANCE SENIOR INCOME TRUST, as a Lender
                         By: Eaton Vance Management, as Investment Advisor

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         GRAYSON & CO., as a Lender
                         By: Boston Management and Research, as Investment
                         Advisor

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

<PAGE>

                         OXFORD STRATEGIC INCOME FUND, as a Lender
                         By: Eaton Vance Management, as Investment Advisor

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________

                         SENIOR DEBT PORTFOLIO, as a Lender
                         By: Boston Management and Research, as Investment
                         Advisor

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________
<PAGE>

                         ERSTE BANK DER OESTERREICHISCHEN SPARKASSEN AG, as a
                         Lender

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________

                         By:_________________________________________________
                            Name:____________________________________________
                            Title:___________________________________________
<PAGE>

                         FC-CBO II LIMITED, as a Lender

                         By:           /s/
                            -----------------------------------------
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         FIDELITY ADVISOR SERIES II: FIDELITY ADVISOR HIGH
                         INCOME FUND, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________

                         VARIABLE INSURANCE PRODUCTS FUND II: ASSET MANAGER
                         PORTFOLIO, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________

                         VARIABLE INSURANCE PRODUCTS FUND II: ASSET MANAGER
                         GROWTH PORTFOLIO, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         FIRST DOMINION FUNDING III, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         FIRST UNION NATIONAL BANK, as a Lender

                         By:           /s/
                            -----------------------------------------
                            Name:  Mark L. Cook
                            Title: Senior Vice President
<PAGE>

                         FLEET NATIONAL BANK, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         FORTIS CAPITAL CORP., as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         FRANKLIN FLOATING RATE TRUST, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         THE FUJI BANK, LIMITED, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         GALAXY CLO 1999-1, LTD., as a Lender
                         By:SAI Investment Adviser, Inc.,
                         its Collateral Agent

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         GENERAL ELECTRIC CAPITAL CORPORATION, as a
                         Lender

                         By:           /s/
                            -----------------------------------------
                            Name:  Brian P. Ward
                            Title: Manager - Operations
<PAGE>

                         HOWARD BANK, N.A., as a Lender

                         By:           /s/
                            -----------------------------------------
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         IBM CREDIT CORPORATION, as a Lender

                         By:              /s/
                            ----------------------------------------------------
                            Name: Ronald J. Bachner
                            Title: Manager
<PAGE>

                         KEMPER FLOATING RATE FUND, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         KEY CORPORATE CAPITAL INC., as a Lender

                         By:                 /s/
                            ----------------------------------------------------
                            Name: Jason R. Weaver
                            Title: Senior Vice President
<PAGE>

                         KZH CYPRESSTREE-1 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH ING-1 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH ING-2 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH ING-3 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH RIVERSIDE LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         KZH SHOSHONE LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH SOLEIL-2 LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         KZH STERLING LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         LEHMAN COMMERCIAL PAPER INC., as a Lender

                         By:                   /s/
                            ----------------------------------------------------
                            Name: G. Andrew Keith
                            Title: Authorized Signatory
<PAGE>

                         MAGNETITE ASSET INVESTORS III L.L.C., as a Lender

                         By:                      /s/
                            ----------------------------------------------------
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         MERRILL LYNCH GLOBAL INVESTMENT SERIES: INCOME
                         STRATEGIES PORTFOLIO, as a Lender
                         By: Merrill Lynch Investment Managers, L.P., as
                             Investment Advisor

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         MERRILL LYNCH PRIME RATE PORTFOLIO, as a Lender
                         By: Merrill Lynch Investment Managers, L.P., as
                             Investment Advisor

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         MASTER SENIOR FLOATING RATE TRUST, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         MERRILL LYNCH SENIOR FLOATING RATE FUND, INC., as a
                         Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         SENIOR HIGH INCOME PORTFOLIO, INC., as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         DEBT STRATEGIES FUND, INC., as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         LONGHORN CDO (CAYMAN) LTD., as a Lender
                         By: Merrill Lynch Asset Management, L.P., as Attorney
                             In Fact

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         METROPOLITAN LIFE INSURANCE COMPANY, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         THE MITSUBISHI TRUST AND BANKING CORPORATION, as a
                         Lender

                         By:                    /s/
                            ----------------------------------------------------
                            Name: Toshihiro Hayashi
                            Title: Senior Vice President
<PAGE>

                         MONY LIFE INSURANCE COMPANY, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         MORGAN STANLEY DEAN WITTER PRIME INCOME TRUST, as a
                         Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         MOUNTAIN CAPITAL CLO I, LTD., as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         MUIRFIELD TRADING LLC, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         OLYMPIC FUNDING TRUST, SERIES 1999-1, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         PPM SPYGLASS FUNDING TRUST, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         WINGED FOOT FUNDING TRUST, as a Lender

                         By:                    /s/
                            ----------------------------------------------------
                            Name: Ann E. Morris
                            Title: Authorized Agent
<PAGE>

                         NATEXIS BANQUES POPULAIRES, as a Lender

                         By:                   /s/
                            ----------------------------------------------------
                            Name: Cynthia E. Sachs
                            Title: VP, Group Manager

                         By:                   /s/
                            ----------------------------------------------------
                            Name: Elizabeth A. Harker
                            Title: Assistant Vice President
<PAGE>

                         NATIONAL CITY BANK, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         OCTAGON INVESTMENT PARTNERS II, LLC, as a Lender
                         By: Octagon Credit Investors, LLC, as sub-investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         OCTAGON INVESTMENT PARTNERS III, LTD., as a Lender
                         By: Octagon Credit Investors, LLC, as Portfolio
                         Manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         OPPENHEIMER SENIOR FLOATING RATE FUND, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         ING PILGRIM SENIOR INCOME FUND, as a Lender
                         By: ING Pilgrim Investments, Inc., as its investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         ML CLO XV PILGRIM AMERICA (CAYMAN) LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         ML CLO XX PILGRIM AMERICA (CAYMAN) LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         PILGRIM CLO 1999-1 LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         PILGRIM PRIME RATE TRUST, as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________

                         SEQUILS-PILGRIM 1, LTD., as a Lender
                         By: Pilgrim Investments, Inc., as its investment
                         manager

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         PNC BANK, NATIONAL ASSOCIATION, as a Lender

                         By:____________________________________________________
                            Name:_______________________________________________
                            Title:______________________________________________
<PAGE>

                         ROYAL BANK OF CANADA, as a Lender

                         By:           /s/
                            ----------------------------------------
                            Name:  Charles Romano
                            Title: Senior Manager
<PAGE>

                         SANKATY HIGH YIELD PARTNERS II, L.P., as a Lender
                         under the Loan Agreement

                         By:           /s/
                            ----------------------------------------------------
                            Name:  Diane J. Exter
                            Title: Managing Director, Portfolio Manager

                         Sankaty Advisors, Inc. as Collateral Manager for GREAT
                         POINT CLO 1999-1 LTD., as Term Lender and as a Lender
                         under the Loan Agreement

                         By:           /s/
                            ----------------------------------------------------
                            Name:  Diane J. Exter
                            Title: Managing Director, Portfolio Manager
<PAGE>

                         SEABOARD CLO 2000 LTD, as a Lender

                         By:_____________________________________________
                            Name:________________________________________
                            Title:_______________________________________
<PAGE>

                         SENECA CBO II, L.P., as a Lender

                         By:           /s/
                            ---------------------------------------
                            Name:  Charles Dicke
                            Title: Partner

                         SENECA CBO III, LIMITED, as a Lender

                         By:           /s/
                            ---------------------------------------
                            Name:  Charles Dicke
                            Title: Partner
<PAGE>

                         SEQUILS-CUMBERLAND I, LTD., as a Lender
                         By: Deerfield Capital Management, L.L.C., as its
                         Collateral Manager

                         By:________________________________________________
                            Name:___________________________________________
                            Title:__________________________________________

                         SEQUILS-CUMBERLAND I, LLC., as a Lender
                         By: Deerfield Capital Management, L.L.C., as its
                         Collateral Manager

                         By:________________________________________________
                            Name:___________________________________________
                            Title:__________________________________________
<PAGE>

                         SUNTRUST BANK, as a Lender

                         By:_________________________________________
                            Name:____________________________________
                            Title:___________________________________
<PAGE>

                         TEXTRON FINANCIAL CORPORATION, as a Lender

                         By:           /s/
                            -----------------------------------------------
                            Name:  Matthew J. Colgan
                            Title: Director
<PAGE>

                         TITANIUM CBO I, LTD., as a Lender

                         By:           /s/
                            -------------------------------------------
                            Name:______________________________________
                            Title:_____________________________________
<PAGE>

                         UNION BANK OF CALIFORNIA, N.A., as a Lender

                         By:           /s/
                            ------------------------------------------------
                            Name:  Stender F. Sweeney, II
                            Title: Vice President
<PAGE>

                         VAN KAMPEN CLO I, LIMITED, as a Lender
                         By: Van Kampen Management, Inc., as Collateral Manager

                         By:           /s/
                            ----------------------------------------------------
                            Name:  Darvin D. Pierce
                            Title: Principal

                         VAN KAMPEN CLO II, LIMITED, as a Lender
                         By: Van Kampen Management, Inc., as Collateral Manager

                         By:           /s/
                            ----------------------------------------------------
                            Name:  Darvin D. Pierce
                            Title: Principal

                         VAN KAMPEN SENIOR INCOME TRUST, as a Lender
                         By: Van Kampen Investment Advisory Corp.

                         By:           /s/
                            ----------------------------------------------------
                            Name:  Darvin D. Pierce
                            Title: Principal
<PAGE>

                         WEBSTER BANK, as a Lender

                         By:____________________________________________
                            Name:_______________________________________
                            Title:______________________________________

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00024-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00024-of-00352.parquet"}]]