<PAGE>
                                                                  EXHIBIT 10.57

                   LIMITED GUARANTY AND SURETYSHIP AGREEMENT

                                                               Contract No. 2911

--------------------------------------------------------------------------------

         THIS LIMITED GUARANTY AND SURETYSHIP AGREEMENT (this "AGREEMENT") is
entered into effective as of JULY 24, 2001 by PSC OF NEW YORK, L.L.C., A
DELAWARE LIMITED LIABILITY COMPANY ("SURETY") to and for the benefit of DVI
FINANCIAL SERVICES INC. ("DVI").

                                   BACKGROUND

         A.       DVI has agreed, or may in the future agree, to extend,
maintain or continue certain loans, leases or other credit facilities
(collectively, the "CREDIT FACILITIES") to or for the benefit of SOUTH SHORE
OPERATING COMPANY, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY (individually
and collectively, the "OBLIGOR").

         B.       Surety has a direct or indirect economic interest in Obligor
and Surety will be directly and materially benefited by the extension of the
Credit Facilities by DVI to Obligor.

         C.       DVI, as a condition to its agreement to extend, maintain or
continue such Credit Facilities to Obligor, and as a material inducement
thereto, has required that Surety execute this Agreement for all of the
purposes hereinafter set forth.

                  NOW, THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged and affirmed, and
intending to be legally bound hereby, Surety agrees as follows:

                  1.       SPECIFIC DEFINITIONS. As used in this Agreement, the
following terms (whether used in the plural or singular form) will mean:

                           "AFFILIATE" means, with respect to any Person, any
other Person that directly or indirectly Controls, is controlled by or is under
common Control with that Person.

                           "CONTROL" means (a) the ownership of a majority of
the voting power of all classes of voting stock of a corporation, (b) the
ownership of a majority of the beneficial interest in income and/or capital of
a Person (other than a corporation or an individual) or (c) possession,
directly or indirectly, of power to direct or cause the direction of management
or policies (whether through ownership of securities or other interests in a
Person (other than an individual), partnership, by contract or otherwise).

                           "EVENT OF DEFAULT" has the meaning specified in
SECTION 6 hereof.

                           "GOVERNMENTAL AUTHORITY" means any governmental or
political subdivision or any agency, authority, bureau, central bank,
commission, department or instrumentality thereof, or any court, tribunal,
grand jury or arbitrator, in any case, whether foreign or domestic.

                           "GUARANTEED OBLIGATIONS" means (a) the due and
punctual payment and performance by each Obligor of its respective obligations
with respect to all loans, leases and other credit facilities owed by it to DVI
or any Affiliate of DVI, whether now existing or hereafter arising (including,
without limitation, those owed by Obligor to others and acquired by DVI or any
Affiliate of DVI by purchase, assignment, or otherwise) and whether direct or
indirect, primary or as guarantor or surety, absolute or contingent, liquidated
or unliquidated, matured or unmatured and (b) any of the foregoing that arises
after the filing of a petition by or against an Obligor, or any of them, under
the United States Bankruptcy Code even if the obligations do not accrue because
of the automatic stay under the United States Bankruptcy Code Section 362 or
otherwise and (c) the payment on demand of all Lender Expenses (as defined in
the Loan Documents).

                           "LOAN DOCUMENTS" means all certificates, documents,
instruments, agreements and riders delivered by any Obligor or any other Person
to DVI pursuant to the terms of, or otherwise in connection with, this
Agreement or any of the Guaranteed Obligations, as the same may be amended,
increased, decreased, modified, replaced, supplemented, renewed or extended
from time to time.


                                                                    Page 1 of 1
<PAGE>

                                                               Contract No. 2911

                           "MATERIAL ADVERSE EFFECT" means, with respect to
Surety or any event or circumstance, a material adverse change in (a) the
business, assets, financial condition or operations of Surety or (b) the
ability of Surety to perform the Guaranteed Obligations.

                           "PERSON" means an individual, corporation,
partnership, limited liability company, trust, unincorporated association,
joint venture, joint-stock company, government (including, without limitation,
political subdivisions), Governmental Authority or any other entity.

                  2.       THE GUARANTY. Subject to the limitations on the
amount of Surety's liability hereunder as described in Rider A attached hereto,
Surety hereby irrevocably, unconditionally and absolutely guarantees to DVI,
its successors, endorsees and assigns (a) the prompt payment when due, whether
at maturity or upon earlier acceleration, of all Guaranteed Obligations and (b)
the prompt and complete compliance with and performance by each Obligor of all
covenants, agreements, indemnities and other obligations to be performed by
each Obligor pursuant to the terms of the Loan Documents.

                  3.       GUARANTEED OBLIGATIONS ABSOLUTE AND UNCONDITIONAL.
Subject to the limitations on the amount of Surety's liability hereunder as
described in Rider A attached hereto, this Agreement will constitute an (a)
agreement of suretyship as well as of guaranty and (b) absolute and
unconditional undertaking by Surety with respect to the payment and performance
of the Guaranteed Obligations by each Obligor. The liability of Surety
hereunder will be direct and may be enforced without DVI being required to
resort to any other right, remedy or security. This Agreement will be
enforceable against Surety, its successors and assigns, without the necessity
of any notice of (i) acceptance of this Agreement, (ii) DVI's intention to act
in reliance hereon, (iii) any loan, lease or other credit facility to or other
transaction between DVI and any Obligor, or (iv) any default by any Obligor,
all of which Surety hereby expressly waives.

                  4.       FURTHER UNDERTAKINGS.

                           (a)      Surety expressly: (i) agrees that the
validity of this Agreement will in no way be terminated, affected or impaired
by reason of the assertion or the failure to assert by DVI against any Obligor,
or its successors or assigns, or any collateral securing the Guaranteed
Obligations of any of the rights or remedies reserved pursuant to the Loan
Documents or otherwise available to DVI at law or in equity, (ii) waives any
right that Surety might otherwise have under any statute, rule of law or
practice or custom to require DVI to take any action against any Obligor or to
proceed against or exhaust any security held by DVI before proceeding against
Surety, (iii) except for notices expressly required hereunder, waives any
notice of (A) any presentment, demand, protest, notice of protest and of
dishonor, notices of default and all other notices with respect to any of the
Guaranteed Obligations and (B) the commencement or prosecution of any
enforcement proceeding, including any proceeding in any court, against any
Obligor or any other person or entity with respect to any of the Guaranteed
Obligations and (iv) agrees that any failure by DVI to exercise any right
hereunder will not be construed as a waiver of the right to exercise the same
or any other right at any other time and from time to time thereafter.

                           (b)      Until the earlier of (i) all of the
Guaranteed Obligations are completely fulfilled to the satisfaction of DVI and
each and every one of the terms, covenants, and conditions of this Agreement
are fully performed, or (ii) Surety has paid to DVI the full amount of its
liability hereunder as limited by the terms of Rider A attached hereto, the
liability of Surety under this Agreement will not be released, discharged or in
any way impaired by: (i) any amendment or modification of, supplement to or
extension or renewal of any Loan Document or any agreements made or to be made
between DVI and any Obligor with respect to any of the Guaranteed Obligations,
(ii) any exercise or non-exercise by DVI of any right, power, remedy or
privilege under or with respect to any Loan Document or this Agreement or any
waiver, consent or approval by DVI with respect to any of the covenants, terms,
conditions or agreements contained in any Loan Document, or any indulgence,
forbearance or extension of time for performance or observance allowed to any
Obligor by DVI from time to time and for any length of time, (iii) any
bankruptcy, insolvency, reorganization, arrangement, readjustment, composition,
liquidation or similar proceeding relating to any Obligor, its successors or
assigns or any of their respective properties, (iv) any transfer by an Obligor
of all or any part of that Obligor's interest in any collateral or (v) any act
or circumstances which might, but for the terms and provisions of this SECTION
4, be deemed a legal or equitable discharge of Surety.

                           (c)      Surety hereby expressly waives and
surrenders any defenses (other than satisfaction of the Guaranteed Obligations)
to Surety's liability hereunder based upon any of the foregoing acts,
omissions, agreements or waivers by DVI, it being the purpose and intent of
this Agreement that the obligations of Surety hereunder are absolute and
unconditional.

                           (d)      Surety hereby further agrees and consents
that DVI may, without affecting the liability of Surety hereunder: (i)
exchange, surrender or release any property pledged by any Obligor or any other
Person or accept additional security for the Guaranteed Obligations or any of
them, (ii) renew, extend and change the terms of any Guaranteed Obligation,


                                                                     Page 2 of 6
<PAGE>

                                                               Contract No. 2911

(iii) waive any of DVI's rights or remedies against any Obligor or any other
surety or guarantor for any Guaranteed Obligation, (iv) release, substitute or
add any one or more surety or other sureties or (v) proceed against Surety
without first resorting to, utilizing or invoking the remedies available
against any Obligor or any other surety or guarantor under the Loan Documents
whether at law or in equity. No enforcement of rights and remedies under this
Agreement or any of the Loan Documents will constitute an irrevocable election
of remedies by DVI. DVI will not be obligated to marshall remedies or assets as
a condition to enforcing the liabilities incurred hereunder against Surety. The
liability of Surety hereunder will be in addition to that stated in any other
guaranty or suretyship agreement, if any, heretofore or hereafter delivered to
DVI.

                           (e)      This Agreement and Surety's payment
obligations hereunder will continue to be effective or be reinstated, as the
case may be, if at any time payment of any of the Guaranteed Obligations is
rescinded or must otherwise be restored or returned by DVI all as though such
payments had not been made. DVI's good faith determination as to whether a
payment must be restored or returned shall be binding on Surety.

                  5.       NO SUBROGATION. Nothing herein contained is intended
or will be construed to give Surety any right of subrogation in, to or under
any Loan Document or any right to participate in any way therein,
notwithstanding any payments by Surety to DVI hereunder. SURETY HEREBY
IRREVOCABLY WAIVES ANY AND ALL RIGHTS IT MAY HAVE AT ANY TIME (WHETHER ARISING
DIRECTLY OR INDIRECTLY, BY OPERATION OF LAW OR CONTRACT) TO ASSERT ANY CLAIM
AGAINST ANY OBLIGOR ON ACCOUNT OF PAYMENTS MADE UNDER THIS AGREEMENT,
INCLUDING, WITHOUT LIMITATION, ANY AND ALL RIGHTS OF SUBROGATION,
REIMBURSEMENT, EXONERATION, CONTRIBUTION OR INDEMNITY, UNLESS AND UNTIL THE
GUARANTEED OBLIGATIONS ARE SATISFIED IN FULL.

                  6.       EVENTS OF DEFAULT. Each of the following shall
constitute an "EVENT OF DEFAULT" hereunder:

                           (a)      If there occurs an "Event of Default" under
any other Loan Document (whether or not an Obligor is a party thereto) and such
event of default is not remedied within the applicable notice, grace or cure
period, if any, provided in such other Loan Document,

                           (b)      If Surety fails to observe or perform any
covenant, condition or agreement to be observed or performed hereunder and such
failure is not cured within thirty (30) days of written notice of such failure
from DVI to Surety. If such failure is capable of cure but cannot be cured
within such thirty (30) day period, Surety will have an additional thirty (30)
days to cure such failure, provided that Surety promptly commences such cure
upon receipt of the foregoing written notice and, at all times thereafter,
diligently pursues such cure. The notice and cure periods set forth in this
Section 6(b) apply only to the extent that the Event of Default in question is
not specifically covered by another subparagraph of this SECTION 6,

                           (c)      If Surety revokes or attempts to revoke
this Agreement or

                           (d)      If a Material Adverse Effect occurs.

All notice, grace and cure periods provided herein shall run concurrently with
all notice, grace and cure periods provided in any other Loan Documents.

                  7.       SET-OFF. DVI shall have a lien upon, a security
interest in and a right of set-off against all property of Surety now or at any
time hereafter in the possession of or under the control of DVI or any DVI
Affiliate in any capacity whatsoever, as security for this undertaking,
provided that Surety may deal with and/or dispose of such property prior to an
Event of Default hereunder. Each such lien, security interest and right of
set-off may be enforced or exercised without demand or notice to Surety, shall
continue in full force and effect unless specifically waived or released by DVI
in writing and shall not be deemed waived by any conduct of DVI, by any failure
of DVI to exercise any such right of set-off or to enforce any such lien or
security interest or by any neglect or delay in so doing.

                  8.       REPRESENTATIONS AND WARRANTIES. Surety acknowledges
that it has received copies of, and read, all of the Loan Documents. Surety, by
its signature hereto, agrees to be bound by all of the terms, conditions,
representations, warranties and covenants set forth in the Loan Documents
applicable to Surety, all of which are incorporated herein and made a part
hereof.

                  9.       DELAY AND WAIVER. No delay or omission to exercise
any right shall impair any such right or be a waiver thereof, but any such
right may be exercised from time to time and as often as may be deemed
expedient. A waiver on one occasion is limited to that particular occasion.


                                                                     Page 3 of 6
<PAGE>

                                                               Contract No. 2911

                  10.      COMPLETE AGREEMENT. This Agreement, together with any
riders, schedules and exhibits attached hereto are the complete agreement of the
parties hereto and supersede all previous understandings relating to the subject
matter hereof. This Agreement may be amended only by an instrument in writing
that explicitly states that it amends this Agreement and is signed by the party
against whom enforcement of the amendment is sought.

                  11.      COUNTERPARTS. This Agreement may be executed in
counterparts, each of which will be an original and all of which will constitute
a single agreement.

                  12.      SEVERABILITY. If any part of this Agreement or the
application thereof to any Person or circumstance is held invalid, the remainder
of this Agreement will be unaffected thereby. The section headings herein are
included for convenience only and may not be deemed to be a part of this
Agreement.

                  13.      BINDING EFFECT; ASSIGNMENT. This Agreement will be
binding upon and inure to the benefit of Surety and DVI and their respective
successors and assigns, except that Surety will not have the right to assign or
delegate its rights or obligations under any of such documents. DVI may at any
time assign or grant participation in all or any portion of this Agreement and
the amounts due thereunder.

                  14.      INTERPRETATION. All references herein to Surety or
DVI will include their respective successors or assigns.

                  15.      NOTICES. All notices, requests and other
communications made or given in connection with this Agreement will be in
writing and will be deemed to be received (a) upon personal delivery to the
individual or division or department to whose attention notices to a party are
to be addressed by private carrier, (b) three (3) business days after being sent
by registered or certified mail, return receipt requested or (c) upon confirmed
receipt by telecopy or e-mail with the original forwarded by first-class mail,
in all cases, with charges prepaid, addressed to Surety, at the address set
forth on the signature page hereon and to DVI, at the addresses set forth below:

To DVI:                                     With copies to:

         DVI Financial Services Inc.                 DVI, Inc.
         2500 York Road                              2500 York Road
         Jamison, PA 18929                           Jamison, PA 18929
         Attention: Chief Credit Officer             Attention: Legal Department
         Telephone: (215) 488-5000                   Telephone: (215) 488-5000
         Facsimile: (215) 488-5010                   Facsimile: (215) 488-5415
         E-Mail: DVI@dvi-inc.com                     E-Mail: DVI@dvi-inc.com

Any party may change such address by sending notice of the change to the other
parties; such change of address is effective only upon actual receipt of such
notice by the other parties.

                  16.      GOVERNING LAW. ALL ACTS AND TRANSACTIONS HEREUNDER
AND THE RIGHTS AND OBLIGATION'S OF THE PARTIES HERETO ARE GOVERNED, CONSTRUED
AND INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE COMMONWEALTH OF PENNSYLVANIA
WITHOUT RESORT TO PRINCIPLES OF CONFLICTS OF LAWS.

                  17.      JURISDICTION. The state and federal courts in the
Commonwealth of Pennsylvania will have jurisdiction over all matters arising out
of this Agreement and the Loan Documents; provided, however, that nothing
contained herein will prohibit DVI from initiating action against Surety in any
jurisdiction in which Surety resides or is located, as the case maybe. Service
of process in any such proceeding will be effective if mailed to Surety at the
address described in SECTION 15 of this Agreement. Surety waives any right it
may have to assert the defense of forum non conveniens or to object to such
venue in any such proceeding.

                  18.      WAIVER OF TRIAL BY JURY. DVI AND SURETY HEREBY WAIVE
THE RIGHT TO TRIAL BY JURY OF ANY MATTERS ARISING OUT OF THIS AGREEMENT OR ANY
OF THE LOAN DOCUMENTS OR THE CONDUCT OF THE RELATIONSHIP BETWEEN DVI AND SURETY.
EACH PARTY HERETO ACKNOWLEDGES THAT SUCH WAIVER HAS BEEN GRANTED AFTER
CONSULTATION WITH COUNSEL.


                                                                     Page 4 of 6
<PAGE>

                                                               Contract No. 2911

                  19.      PRESS RELEASE. Surety will not issue any press
release or make any public announcement relating to this Agreement or any Credit
Facilities extended to Obligor without DVI's express written consent except for
disclosures required by applicable law.

                  20.      AUTOMATIC ADJUSTMENT IN LIABILITY. In the event that
the guaranty and suretyship established hereunder would constitute a "fraudulent
conveyance" under any applicable Federal, state or local statute, regulation or
court decision and thereby result in the invalidity or unenforceability of this
Agreement, in whole or in part, with respect to Surety, then the maximum
liability of Surety hereunder will automatically be limited to the greatest
dollar amount to which Surety could be liable hereunder without this Agreement
so constituting a fraudulent conveyance with respect to Surety with the intent
and effect that this Agreement will be so interpreted and construed to be valid
and enforceable to the maximum extent permitted by law.

                  21.      CONTRACT NUMBER. The inclusion of a Contract Number
herein is not intended, and should not be interpreted, to limit in any way the
enforceability or applicability of this Agreement solely to the Guaranteed
Obligations relating to such Contract Number.

         [THE REMAINDER OF THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK]


                                                                     Page 5 of 6
<PAGE>

                                                               Contract No. 2911

               SIGNATURE PAGE - GUARANTY AND SURETYSHIP AGREEMENT

         IN WITNESS WHEREOF, Surety has executed this Agreement by its duly
authorized representative effective as of the date first above.

                                    PSC OF NEW YORK, L.L.C., A DELAWARE LIMITED
                                    LIABILITY COMPANY



                                    By: /s/ Gary W. Rasmussen
                                       ----------------------------------------
                                    Name: Gary W. Rasmussen
                                         --------------------------------------
                                    Title: Secretary/Treasurer
                                          -------------------------------------
                                    Address: 5847 San Felipe Suite 2375
                                            -----------------------------------
                                             Houston, TX 77057
                                    -------------------------------------------
                                    Contact Person: Gary W. Rasmussen
                                                   ----------------------------
                                    Telephone: 713-532-8500
                                              ---------------------------------
                                    Facsimile: 713-532-8484
                                              ---------------------------------
                                    E-Mail: GaryR@pscasc.com
                                           ------------------------------------


                                                                     Page 6 of 6
<PAGE>

                           RIDER A TO LIMITED GUARANTY
                            AND SURETYSHIP AGREEMENT
                               (LIMITED RECOURSE)

(R)2000, DVI Financial Services Inc., All Rights Reserved      Contract No. 2911

         THIS RIDER A TO LIMITED GUARANTY AND SURETYSHIP AGREEMENT (this
"RIDER") is entered into effective as of July 24, 2001, by and between PSC OF
NEW YORK, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY ("SURETY") and DVI
FINANCIAL SERVICES INC. ("DVI")

                                   BACKGROUND

         A.       By a certain Limited Guaranty and Suretyship Agreement of even
date herewith (the "GUARANTY"), Surety has agreed to guarantee and become surety
for all Guaranteed Obligations, subject to the limitations set forth herein.

         B.       All capitalized terms not otherwise defined herein have the
meanings set forth in the Guaranty.

                  NOW, THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged and affirmed, and
intending to be legally bound hereby, the parties hereto agree as follows:

                  1.       LIMITATION ON LIABILITY. The liability of Surety
under the Guaranty will be limited to (a) the Collateral pledged by Surety to
DVI under that certain Master Security Agreement dated JULY 24, 2001, plus (b)
the amount of all Lender Expenses actually incurred by DVI to enforce the
Guaranty, plus (c) interest on the sum of (a) and (b) accrued at the rate of
eighteen (18%) per annum from the date of demand until payment in full of all
amounts due under the Guaranty.

                  2.       EFFECT OF RIDER. All terms and conditions of the
Guaranty not expressly modified hereby are in full force and effect as ratified
and confirmed by the parties hereto.

         IN WITNESS WHEREOF, the parties have executed this Rider by their duly
authorized representatives effective as of the date first above written.

                                    PSC OF NEW YORK, L.L.C., A DELAWARE LIMITED
                                    LIABILITY COMPANY



                                    By:
                                       ----------------------------------------
                                    Name:
                                         --------------------------------------
                                    Title:
                                          -------------------------------------

                                    DVI FINANCIAL SERVICES INC.



                                    By:
                                       ----------------------------------------
                                    Name:
                                         --------------------------------------
                                    Title:
                                          -------------------------------------


                                                                     Page 7 of 1
<PAGE>

                           RIDER A TO LIMITED GUARANTY
                            AND SURETYSHIP AGREEMENT
                               (LIMITED RECOURSE)

                                                               Contract No. 2911

         THIS RIDER A TO LIMITED GUARANTY AND SURETYSHIP AGREEMENT (this
"RIDER") is entered into effective as of July 24, 2001, by and between PSC OF
NEW YORK, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY ("SURETY") and DVI
FINANCIAL SERVICES INC. ("DVI")

                                   BACKGROUND

         A.       By a certain Limited Guaranty and Suretyship Agreement of even
date herewith (the "GUARANTY"), Surety has agreed to guarantee and become surety
for all Guaranteed Obligations, subject to the limitations set forth herein.

         B.       All capitalized terms not otherwise defined herein have the
meanings set forth in the Guaranty.

                  NOW, THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged and affirmed, and
intending to be legally bound hereby, the parties hereto agree as follows:

                  1.       LIMITATION ON LIABILITY. The liability of Surety
under the Guaranty will be limited to (a) the Collateral pledged by Surety to
DVI under that certain Master Security Agreement dated JULY 24, 2001, plus (b)
the amount of all Lender Expenses actually incurred by DVI to enforce the
Guaranty, plus (c) interest on the sum of (a) and (b) accrued at the rate of
eighteen (18%) per annum from the date of demand until payment in full of all
amounts due under the Guaranty.

                  2.       EFFECT OF RIDER. All terms and conditions of the
Guaranty not expressly modified hereby are in full force and effect as ratified
and confirmed by the parties hereto.

<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Rider by their duly
authorized representatives effective as of the date first above written.

                                    PSC OF NEW YORK, L.L.C., A DELAWARE LIMITED
                                    LIABILITY COMPANY



                                    By:
                                       ----------------------------------------
                                    Name:
                                         --------------------------------------
                                    Title:
                                          -------------------------------------

                                    DVI FINANCIAL SERVICES INC.



                                    By:
                                       ----------------------------------------
                                    Name:
                                         --------------------------------------
                                    Title:
                                          -------------------------------------


                                       2