<PAGE>

                                                                    Exhibit 10.6


                            THIRD AMENDMENT TO MORTGAGE
                                     (MEREDITH)


     This Third Amendment to Mortgage made as of the 4th day of September, 1998
by and between DM Management Company ("Mortgagor") and Citizens Bank of
Massachusetts ("Mortgagee").

     Reference is made to a certain Mortgage made as of the 30th day of July,
1997 by and between Mortgagor and Mortgagee, which Mortgage is recorded in Book
1429, Page 772 at the Belknap County, New Hampshire Registry of Deeds, as
amended by a certain First Amendment to Mortgage dated October 31, 1997,
recorded in Book 1442, Page 0267 and by a certain Second Amendment to Mortgage
dated March 5, 1998, recorded in Book 1457, Page 0998 at said Registry of Deeds
(collectively, the "Mortgage").

     For good and valuable consideration paid by each of the parties to the
other, and in further consideration of the mutual covenants and agreements
herein contained, it is agreed by and between Mortgagor and Mortgagee that the
Mortgage is hereby amended by deleting the entire paragraph following the word
"WITNESSETH" and the following is hereby inserted in lieu thereof.

          The Mortgagor hereby grants to Mortgagee, with mortgage covenants, the
     real property described on Exhibit A (hereinafter called the "Mortgaged
     Premises") to secure  (a) the full payment of the sum of $8,500,000.00, or
     such lesser amount which shall have been advanced, together with interest
     and other charges, all as provided in a certain "Revolving Note" of the
     Mortgagor to the order of the Mortgagee dated June 5, 1997, which note was
     amended and replaced by a certain "Replacement Revolving Note" dated
     October 31, 1997 in the face amount of $8,500,000.00, which Note was
     amended and replaced by a certain "Second Replacement Revolving Note" dated
     September 4, 1998 in the face amount of $23,500,000, all as provided in a
     certain Loan Agreement dated June 5, 1997 as amended and restated as of
     March 5, 1998 and as further amended and restated dated September 4, 1998
     herewith and as the same may hereafter be amended (collectively, the "Loan
     Agreement") together with all substitutions or replacements therefor and
     all renewals or extensions thereof and the full performance of all other
     obligations of the maker of said note as provided therein; (b) the full
     payment of the sum of $1,650,000.00, as provided in a certain "Real Estate
     Note" (as defined in the Loan Agreement) of the Mortgagor to the order of
     the Mortgagee, dated July 30, 1997, executed and delivered by the Mortgagor
     to the Mortgagee, pursuant to the Loan Agreement in the face amount of
     $1,650,000.00, with interest and other charges as provided therein,
     together with all substitutions and replacements therefor and all renewals
     and extensions thereof and the full performance of all other obligations of
     the maker of said note as provided therein and under a certain "Real Estate
     Mortgage" (as defined in the Loan Agreement) executed and delivered in
     connection therewith; (c) the full payment of the sum of $3,600,000.00,
     with interest and other charges, all as provided in a certain "Term Note"
     (as defined in the Loan Agreement) of the Mortgagor to the order of the
     Mortgagee, dated June 5, 


<PAGE>

     1997, executed and delivered by the Mortgagor to the Mortgagee pursuant to
     the Loan Agreement, in the original face amount of $3,600,000.00, together
     with all substitutions or replacements therefor and all renewals or
     extensions thereof and the full performance of all other obligations of the
     maker of said note as provided therein; (d) the full payment of the sum of
     $4,300,000.00, with interest and other charges, all as provided in a
     certain "New Bridge Note" (as defined in the Loan Agreement) of the
     Mortgagor to the order of the Mortgagee dated as of March 5, 1998, executed
     and delivered by the Mortgagor to the Mortgagee pursuant to the Loan
     Agreement, in the original face amount of $4,300,000.00, as amended and
     replaced by that certain "Replacement New Bridge Note" (as defined in the
     Loan Agreement) dated September 4, 1998, together with all substitutions
     and replacements therefor and all renewals and extensions thereof and the
     full performance of all other obligations of the maker of said note as
     provided therein, and under a certain "Bridge Mortgage" (as defined in the
     Loan Agreement), executed and delivered in connection therewith as the same
     may be amended from time to time; (e) the full payment of the sum of
     $17,000,000.00 as provided in a certain "Short Term Revolving Note" (as
     defined in the Loan Agreement) of the Mortgagor to the order of the
     Mortgagee dated March 5, 1998 pursuant to the Loan Agreement in the face
     amount of $17,000,000.00, as amended and replaced by that certain
     "Replacement Short Term Revolving Note" (as defined in the Loan Agreement)
     dated September 4, 1998, together with interest and other charges as
     provided therein, and all renewals and extensions thereof and the full
     performance of all other obligations of the maker of said note as provided
     therein and a certain Assignment of Certificate of Deposit dated as of
     March 5, 1998, as amended dated September 4, 1998, executed and delivered
     in connection therewith as the same may hereafter be amended; (f) the full
     payment and performance by the Mortgagor of all other indebtedness,
     obligations and liabilities of the Mortgagor to the Mortgagee under the
     Loan Agreement, direct or indirect, absolute or contingent, now existing or
     hereafter arising (including, without limitation, all "Obligations", as
     defined in the Loan Agreement) which Loan Agreement provides, among other
     things, for the establishment of a "Revolving Loan" (as defined therein)
     and for the issuance of Letters of Credit pursuant to "L/C Applications"
     (as defined therein) pursuant to which "Advances" (as defined therein) may
     be made from time to time, and for repayment of all or a portion of the
     outstanding balance of such Advances together with interest and other
     charges, all in accordance therewith, and for the grant of "Loans" (as
     defined therein) as provided therein; and (g) the full payment and
     performance of all covenants and agreements herein contained or referred to
     on the part of the Mortgagor to be kept and performed (collectively
     hereafter referred to as "Obligations").

     In all other respects, the said Mortgage (as intended herein) shall hereby
remain in full force and effect in accordance with its terms.

     IN WITNESS WHEREOF, Mortgagor has caused this instrument to be executed on
this 4th day of September, 1998.

Witness                               DM MANAGEMENT COMPANY


/s/ Richard J. Snyder
------------------------------        By:   /s/ Olga L. Conley
                                         ----------------------------------
                                         Olga L. Conley, Chief Financial Officer


<PAGE>

                           COMMONWEALTH OF MASSACHUSETTS

COUNTY OF SUFFOLK

     On this 4th day of September, 1998, before me, personally appeared the
undersigned officer, Olga L. Conley, known to me (or satisfactorily proven) to
be the person whose name is subscribed to the foregoing written instrument as
the Chief Financial Officer of DM Management Company in its name and on its
behalf and acknowledged that she executed the same for the purposes therein
contained.

     IN WITNESS WHEREFORE I have hereunto set my hand and official seal.


                              /s/ Barbara Jean Apel
                              -----------------------------------
                              Notary Public
                              My Commission Expires:   8/12/99
                                                     ------------