Document:

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                                                                     EXHIBIT 4.9

                          REGISTRATION RIGHTS AGREEMENT

                                 BY AND BETWEEN

                               THE VIALINK COMPANY

                                       AND

                              AGE INVESTMENTS, INC.

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                                TABLE OF CONTENTS

<TABLE>
<S>                                                                                                              <C>
ARTICLE 1 DEFINITIONS.............................................................................................1

ARTICLE 2 REGISTRATION RIGHTS.....................................................................................3
         2.1      Piggyback Registrations.........................................................................3
         2.2      Registration Procedures.........................................................................4
         2.3      Payment of Expenses.............................................................................7
         2.4      Participation in Underwritten Registrations.....................................................7
         2.5      Information of the Holder.......................................................................7
         2.6      Rule 144 Information............................................................................7

ARTICLE 3 INDEMNIFICATION.........................................................................................7
         3.1      Indemnification by the Company..................................................................7
         3.2      Indemnification by Holder.......................................................................8
         3.3      Notice: Defense of Claims.......................................................................8
         3.4      Contribution....................................................................................8
         3.5      Survival........................................................................................9

ARTICLE 4 MISCELLANEOUS...........................................................................................9
         4.1      Notices.........................................................................................9
         4.2      Interpretation.................................................................................10
         4.3      Counterparts...................................................................................10
         4.4      Entire Agreement...............................................................................10
         4.5      Amendments and Waivers.........................................................................10
         4.6      Successors and Assigns.........................................................................10
         4.7      Severability...................................................................................11
         4.8      Remedies Cumulative............................................................................11
         4.9      Governing Law..................................................................................11
         4.10     Rules of Construction..........................................................................11
         4.11     Currency.......................................................................................11
</TABLE>

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                          REGISTRATION RIGHTS AGREEMENT

     THIS REGISTRATION RIGHTS AGREEMENT (the "Agreement") is made and entered
into as of April ___, 2000, by and between The viaLink Company, a Delaware
corporation (together with any successor entity, the "Company"), and AGE
Investments, Inc. (the "Holder").

                                R E C I T A L S:

         A. The Company and certain of its investors, are parties to a
Securities Purchase Agreement, dated March 22, 2000 (the "Purchase Agreement"),
providing, among other things, for such investors acquisition of shares of
Common Stock, par value $0.001 per share, of the Company and a warrant to
purchase shares of Common Stock of the Company.

         B. The Company and A.G. Edwards & Sons, Inc. ("AG Edwards") are parties
to an Engagement Letter, dated February 25, 2000 (the "Letter"), providing,
among other things for the issuance to AG Edwards of a Warrant (the "Warrant")
to purchase shares of the Company's Common Stock (the "Shares"), which Warrant
AG Edwards has requested be issued in the name of the Holder.

         C. AG Edwards, pursuant to the Letter has located, on behalf of the
Company, Millennium Partners, L.P., who is one of the investors who is a party
to the Purchase Agreement (the "Services").

         D. As partial consideration for the performance of the Services, the
Company is entering into this Agreement.

                               A G R E E M E N T:

     NOW, THEREFORE, in consideration of the foregoing and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

                                   ARTICLE 1

                                  DEFINITIONS

     For purposes of this Agreement, the following terms shall have the meanings
indicated:

     "Closing" means the closing of the transactions contemplated by the
Purchase Agreement.

     "Commission" means the United States Securities and Exchange Commission.

     "Common Stock" means the Company's common stock, par value $0.001 per
share.

     "1933 Act" means the United States Securities Act of 1933, as amended.

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     "Other Securities" means any stock (other than Common Stock) or other
securities of the Company or any other person (corporate or otherwise) (i) which
the holder of a Warrant at any time shall be entitled to receive, or shall have
received, on the exercise of the Warrant, in lieu of or in addition to shares of
Common Stock, or (ii) which at any time shall be issuable or shall have been
issued in exchange for or in replacement of shares of Common Stock.

     "Person" means an individual, a partnership, a corporation, an association,
a joint stock company, a trust, a joint venture, an unincorporated organization
and a governmental entity or any department, agency or political subdivision
thereof.

     "Piggyback Registration" means the registration provided for in Section 2.1
hereof.

     "Potential Material Event" means any of the following: (a) the possession
by the Company of material non-public information required to be disclosed in a
Company registration statement and the determination in good faith by the Board
of Directors of the Company that disclosure of such information in the
registration statement at that time would be detrimental to the business and
affairs of the Company; or (b) any material engagement or activity by the
Company that would, in the good faith determination of the Board of Directors of
the Company, if disclosed in the registration statement at such time, be
materially and adversely affected, which determination shall be accompanied by a
good faith determination by the Board of Directors of the Company that the
registration statement would be materially misleading absent the inclusion of
such information.

     "Registration Expenses" means all expenses incident to the Company's
performance of or compliance with Article 2 hereof, including all registration,
Commission filing fees, fees of the National Association of Securities Dealers
or the Nasdaq SmallCap Market, all fees and expenses of complying with
securities or blue sky laws, printing expenses, the fees and disbursements of
counsel for the Company and of its independent public accountants, including the
expenses of "cold comfort" letters required by or incident to such performance
and compliance, and, in the case of a Piggyback Registration pursuant to Section
2.1 hereof that is a firm commitment underwritten public offering, the
reasonable fees and expenses (not to exceed $15,000) of one counsel to all
selling Holders; provided, however, that Registration Expenses shall exclude,
and the sellers of the Registrable Stock being registered shall pay, any
underwriting discounts, commissions and transfer taxes in respect of the
Registrable Stock being registered.

     "Registrable Stock" means (a) all Shares; (b) all shares of Common Stock or
Other Securities issued or issuable upon exercise of the Warrant; and (c) any
securities issued or issuable with respect to such shares of Common Stock or
Other Securities described in (a) or (b) above by way of a stock dividend or
stock split or in connection with a combination or reclassification of shares,
recapitalization, merger, consolidation or other reorganization or otherwise;
provided, however, that any particular Registrable Stock shall cease to be
Registrable Stock when (x) a registration statement with respect to the sale of
such stock shall become effective under the 1933 Act and such stock shall have
been disposed of in accordance with such registration statement, or (y) such
stock shall have been sold pursuant to Rule 144; and provided further, only
securities issued by the Company will be deemed to be Registrable Stock.

     "Rule 144" means Rule 144 (or any successor provision) under the 1933 Act.

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                                   ARTICLE 2

                               REGISTRATION RIGHTS

     2.1 Piggyback Registrations.

         (a) Right to Piggyback. If subsequent to the 90th day after the
     Closing and prior to the fifth anniversary of the Closing the Company
     proposes to register any offering of its securities under the Securities
     Act, whether or not for sale for its own account (other than on Form S-4,
     Form S-8 or any successor form), and the registration form to be used
     permits the registration of an offering of Registrable Stock by a Holder (a
     "Piggyback Registration"), then the Company will give prompt notice to the
     Holder(s) of Registrable Stock of its intention to effect such a
     registration (each a "Piggyback Notice"). Subject to Section 2.1(b) below,
     the Company will include in such registration all shares of Registrable
     Stock that the Holder(s) thereof have requested the Company to include in
     such registration by notice to the Company within 20 days after the date of
     receipt of the Company's notice. Notwithstanding any other provisions of
     this Agreement (including Section 2.2), the process (including timing) of
     causing a Piggyback Registration to become effective and any decision to
     terminate a Piggyback Registration will be within the sole discretion of
     the Company.

         (b) Priority on Registrations. If any Piggyback Registration shall be
     an underwritten offering, the right of any Holder's Registrable Stock to be
     included in such Piggyback Registration shall be conditioned upon such
     Holder's participation in such underwriting and the inclusion of such
     Holder's Registrable Stock in the underwriting to the extent provided
     herein Notwithstanding any other provision of this Agreement, if the
     managing underwriter determines in good faith that marketing factors
     require a limitation of the number of shares to be underwritten, then the
     managing underwriter may exclude shares (including Registrable Stock) from
     the registration and the underwriting, and the number of shares that may be
     included in the registration and the underwriting will be allocated: (i) in
     the case of a registration initiated by the Company for the purpose of
     registering securities to be sold by the Company, first, to the Company,
     second, to any party which as of the date hereof has a contractual right to
     participate in such registration to the extent such party's currently
     existing contractual arrangements prohibit the Company from allowing the
     Holders of Registrable Stock to participate pro rata with such party in
     such registration, third to the Holders of Registrable Stock, and fourth,
     to all other persons requesting that securities be included in such
     registration; and (ii) in the case of a registration initiated by the
     Company for the purpose of registering securities to be sold by security
     holders of the Company, first, to any party which has exercised its
     contractual right to require that the Company initiate such registration,
     second, to any party which as of the date hereof has a contractual right to
     participate in such registration to the extent such party's currently
     existing contractual arrangements prohibit the Company from allowing the
     Holders of Registrable Stock to participate pro rata with such party in

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     such registration, third to the Holders of Registrable Stock, and fourth,
     to all other persons requesting that securities be included in such
     registration. Within the category for the allocation of securities to be
     included in the registration/underwriting to which Holders of Registrable
     Stock are assigned, such Holders will participate pro rata on the basis of
     the number of shares that such Holders have requested (consistent with
     their contractual rights) to be included in the registration. If a Holder
     disapproves of the terms of any such underwriting, such Holder may elect to
     withdraw therefrom by written notice to the Company and the managing
     underwriter. Any Registrable Stock excluded or withdrawn from such
     underwriting shall be excluded and withdrawn from the registration.

     2.2 Registration Procedures. In connection with any registration hereunder,
the Company will use its best efforts to, as soon as practicable, effect the
registration and the sale of such Registrable Stock in accordance with the
intended method of distribution thereof and will:

         (a) prepare and file with the Commission a registration statement with
     respect to such Registrable Stock and use its best efforts to cause such
     registration statement to become effective; provided, however, that before
     filing a registration statement or prospectus or any amendments or
     supplements thereto, the Company will furnish to the counsel, if any,
     selected by the Holder copies of all such documents proposed to be filed,
     which documents will be subject to the reasonable comments of such counsel;

         (b) prepare and file with the Commission such amendments and
     supplements to such registration statement and the prospectus used in
     connection therewith as may be necessary to keep such registration
     statement effective for such period as shall be required for the
     disposition pursuant to the terms of such registration of all Registrable
     Stock covered thereby, and in each such case comply with the provisions of
     the 1933 Act with respect to the disposition of all securities covered by
     such registration statement during such period in accordance with the
     intended methods of distribution by the sellers thereof set forth in such
     registration statement;

         (c) furnish to each seller of Registrable Stock such reasonable number
     of copies of such registration statement, each amendment and supplement
     thereto, in each case including all exhibits, the prospectus included in
     such registration statement (including each preliminary prospectus) and
     such other documents as such seller may reasonably request in order to
     facilitate the disposition of the Registrable Stock then held, owned and
     being registered by such seller;

         (d) use its best efforts to register or qualify such Registrable Stock
     under such other securities or blue sky laws of such jurisdictions within
     the United States as any seller reasonably requests to keep such
     registration or qualification in effect for as long as the relevant
     registration statement is in effect and do any and all other acts and
     things which may be reasonably necessary or advisable to enable such seller
     to consummate the disposition in such jurisdictions of the Registrable
     Stock then held, owned and being registered by such seller; provided,
     however,

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     that the Company will not be required (i) to qualify generally to do
     business in any jurisdiction where it would not otherwise be required to
     qualify but for this subsection (d), (ii) to subject itself to taxation in
     any such jurisdiction or (iii) to consent to general service of process in
     any such jurisdiction;

         (e) notify each seller of such Registrable Stock, at any time when a
     prospectus relating thereto is required to be delivered under the 1933 Act,
     of the happening of any event as a result of which the prospectus included
     in such registration statement contains an untrue statement of a material
     fact or omits any fact necessary to make the statements therein not
     misleading and, at the request of any such seller, the Company will
     promptly prepare a supplement or amendment to such prospectus so that, as
     thereafter delivered to the purchasers of such Registrable Stock, such
     prospectus will not contain an untrue statement of a material fact or omit
     to state any fact necessary to make the statements therein, in light of the
     circumstances under which such statements are made, not misleading;

         (f) cause all such Registrable Stock to be listed on each securities
     exchange on which similar securities issued by the Company are then listed
     and to be qualified for trading on each system on which similar securities
     issued by the Company are from time to time qualified;

         (g) provide a transfer agent and registrar for all such Registrable
     Stock not later than the effective date of such registration statement and
     thereafter maintain such a transfer agent and registrar;

         (h) enter into such customary agreements (including underwriting
     agreements in customary form) and take all such other actions as the
     underwriters, if any, reasonably request in order to expedite or facilitate
     the disposition of such Registrable Stock;

         (i) make available for inspection, subject to execution and delivery
     of customary non-disclosure and non-use agreements, by any underwriter
     participating in any disposition pursuant to such registration statement
     and any attorney, accountant or other agent retained by any such
     underwriter, all financial and other records, pertinent corporate documents
     and properties of the Company, and cause the Company's officers, directors,
     employees and independent accountants to supply, subject to execution and
     delivery of customary non-disclosure and non-use agreements, all
     information reasonably requested by any such underwriter, attorney,
     accountant or agent in connection with such registration statement;

         (j) otherwise use its best efforts to comply with all applicable rules
     and regulations of the Commission, and make available to its security
     holders, as soon as reasonably practicable, an earnings statement covering
     the period of at least 12 months beginning with the first day of the
     Company's first full calendar quarter after the effective date of the
     registration statement, which earnings statement shall satisfy the
     provisions of Section 11(a) of the 1933 Act and Rule 158 thereunder;

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         (k) if such registration relates to an underwritten offering, furnish
     to each seller of Registrable Stock a signed counterpart of

             (x) an opinion of counsel for the Company, which may be the head
         in-house counsel for the Company, and

             (y) a "comfort" letter signed by the independent public
         accountants who have certified the Company's financial statements
         included or incorporated by reference in such registration statement,

     in each case covering substantially the same matters with respect to such
     registration statement (and the prospectus included therein) and, in the
     case of the accountants' comfort letter, with respect to events subsequent
     to the date of such financial statements, as are customarily covered in
     opinions of issuer's counsel and in accountants' comfort letters to be
     delivered to the underwriters in underwritten public offerings of
     securities (and dated the dates such opinions and comfort letters are
     customarily dated) and, in the case of the accountants' comfort letter,
     such other financial matters;

         (l) permit any Holder of Registrable Stock which might be deemed, in
     the reasonable judgment of such Holder, to be an underwriter or a
     controlling person of the Company, to participate in the preparation of
     such registration or comparable statement and to require the insertion
     therein of material, furnished to the Company in writing, which in the
     reasonable judgment of such Holder and its counsel, if any, should be
     included;

         (m) in the event of the issuance of any stop order suspending the
     effectiveness of a registration statement, or of any order suspending or
     preventing the use of any related prospectus or suspending the
     qualification of any Registrable Stock included in such registration
     statement for sale in any jurisdiction, the Company will promptly notify
     each seller of Registrable Stock thereof and will use its best efforts
     promptly to obtain the withdrawal of such order; and

         (n) in connection with any underwritten offering, the Company shall
     have the right to designate the underwriter(s) to manage such offering,
     subject to the approval of the Holder(s) of a majority of the Registrable
     Stock to be included therein, which approval will not be unreasonably
     withheld, conditioned or delayed.

Each Holder agrees that if the Company has delivered preliminary or final
prospectuses to such Holder and after having done so the Company shall give
notice to such Holder that (A) the prospectus needs to be amended or
supplemented to comply with the requirements of the 1933 Act, (B) a stop order
suspending the effectiveness of the registration statement is issued by the
Commission or (C) a Potential Material Event shall exist, then such Holder shall
immediately cease making offers and sales of Registrable Stock and return all
remaining prospectuses to the Company if requested by the Company in such
notice. Following such amendment or supplement, the lifting of any stop order or
such time as the Potential Material Event shall no longer exist, the Company
shall promptly provide to such Holder notice that offers and sales may be
resumed and,

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to the extent appropriate, revised prospectuses, and such Holder shall then be
free to resume making offers of the Registrable Stock, or any portion thereof,
and the Company's obligation to maintain the effectiveness of the registration
statement, if any, shall be extended by an equal amount of time.

     2.3 Payment of Expenses. The Company shall pay all Registration Expenses in
connection with any Piggyback Registration. All fees and disbursements of
counsel (except to the extent comprising "Registration Expenses" pursuant to
Article 1 hereof), accountants and other experts retained by the Holder shall be
borne by the Holder.

     2.4 Participation in Underwritten Registrations. The Holder may not
participate in any registration hereunder which is underwritten unless the
Holder (a) agrees to sell the Holder's securities on the basis provided in any
underwriting arrangements approved by the Person or Persons entitled hereunder
to approve such arrangements; and (b) completes and executes all questionnaires,
powers of attorney, indemnities, standstill or holdback agreements, underwriting
agreements and other documents required under the terms of such underwriting
arrangements, provided that if the Holder's Registrable Stock is included in any
underwritten registration, the Holder shall not be required to make any
representations or warranties to the Company or the underwriters other than
representations and warranties regarding the Holder and the Holder's intended
method of distribution.

     2.5 Information of the Holder. As a condition to participation in any
registration hereunder, the Holder shall furnish to the Company such information
regarding the Holder and the distribution proposed by the Holder as the Company
may reasonably request and as shall be required in connection with any
registration, qualification or compliance contemplated by this Agreement.

     2.6 Rule 144 Information. From and after the date hereof and for so long as
necessary in order to permit the Holders to sell the Registrable Stock pursuant
to Rule 144 under the 1933 Act, the Company will file on a timely basis all
reports required to be filed by it pursuant to Section 13 or 15(d) of the United
States Securities Exchange Act of 1934 and referred to in paragraph (c)(1) of
Rule 144 (or, if applicable, the Company will make publicly available the
information regarding itself referred to in paragraph (c)(2) of Rule 144), in
order to permit the Holders to sell the Registrable Stock, pursuant to the terms
and conditions of the applicable provisions of Rule 144.

                                   ARTICLE 3

                                 INDEMNIFICATION

     3.1 Indemnification by the Company. The Company agrees to indemnify, to the
extent permitted by law, the Holder, its officers and directors and each Person
who controls a Holder (within the meaning of the 1933 Act) against all losses,
claims, damages, liabilities and expenses which arise out of or are based upon
any untrue or alleged untrue statement of material fact contained in any
registration statement, prospectus or preliminary prospectus or any amendment
thereof or supplement thereto or any omission or alleged omission of a material
fact required to be stated therein or necessary to make the statements therein
not misleading, except

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insofar as the same are caused by or contained in any information furnished in
writing to the Company by such Holder, its officers and directors or any Person
who controls such Holder expressly for use therein. In connection with an
underwritten offering, the Company will indemnify such underwriters, their
officers and directors and each Person who controls such underwriters (within
the meaning of the 1933 Act) to the same extent as provided above with respect
to the indemnification of a Holder.

     3.2 Indemnification by Holder. In connection with any registration
statement in which a Holder is participating, each such Holder, severally and
not jointly, will, to the extent permitted by law, indemnify the Company, its
directors and officers and each Person who controls the Company (within the
meaning of the 1933 Act) against any losses, claims, damages, liabilities and
expenses which arise out of or are based upon any untrue or alleged untrue
statement of material fact contained in the registration statement, prospectus
or preliminary prospectus or any amendment thereof or supplement thereto or any
omission or alleged omission of a material fact required to be stated therein or
necessary to make the statements therein not misleading (but only to the extent
that such untrue statement or omission is contained in any information or
affidavit so furnished in writing by such Holder expressly for use therein) and
any failure by each such Holder to deliver a copy of the registration statement
or prospectus or any amendments or supplements thereto; provided, however, that
the obligation to indemnify will be individual to each Holder and will be
limited to the net amount of proceeds received by such Holder from the sale of
Registrable Stock pursuant to such registration statement.

     3.3 Notice: Defense of Claims. Any Person entitled to indemnification
hereunder will (a) give prompt written notice to the indemnifying party of any
claim with respect to which it seeks indemnification and (b) unless in such
indemnified party's reasonable judgment a conflict of interest between such
indemnified and indemnifying parties may exist with respect to such claim,
permit such indemnifying party to assume the defense of such claim with counsel
reasonably satisfactory to the indemnified party; provided, that the failure of
any indemnified party to give notice as provided herein shall not relieve the
indemnifying party of its obligations under this Agreement except to the extent
the indemnifying party is materially prejudiced by such failure. If such defense
is assumed, the indemnified party may participate in such defense at its own
expense and the indemnifying party will not be subject to any liability for any
settlement made by the indemnified party without its consent (but such consent
will not be unreasonably withheld, conditioned or delayed). An indemnifying
party who is not entitled to, or elects not to, assume the defense of a claim
will not be obligated to pay the fees and expenses of more than one counsel (in
addition to local counsel) for all parties indemnified by such indemnifying
party with respect to such claim, unless in the reasonable judgment of any
indemnified party a conflict of interest may exist between such indemnified
party and any other of such indemnified parties with respect to such claim. No
indemnified party shall consent to entry of any judgment or settle any claim or
litigation without the prior written consent of the indemnifying party, which
consent shall not be unreasonably withheld, conditioned or delayed. Each
indemnified party, as a condition to its right to indemnification, will
reasonably cooperate with the indemnifying party (at the expense of the
indemnifying party) in the defense of such claim.

     3.4 Contribution. If the indemnification provided for in this Article 3 is
unavailable or insufficient to hold harmless an indemnified party under Section
3.1 or 3.2, then

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each indemnifying party shall contribute to the amount paid or payable by such
indemnified party as the result of the losses, claims, damages or liabilities
referred to above in such proportion as is appropriate to reflect the relative
fault of the indemnifying party on the one hand and the indemnified party on the
other in connection with the statements and omissions that resulted in such
losses, claims, damages or liabilities. The relative fault shall be determined
by reference to, among other things, whether the untrue or alleged untrue
statement of a material fact or the omission or alleged omission to state a
material fact related to information supplied by the indemnifying party or
information supplied by the indemnified party, and the parties' relevant intent,
knowledge, access to information and opportunity to correct or prevent such
untrue statement or omission. The amount paid by an indemnified party as a
result of the losses, claims, damages or liabilities referred to in the first
sentence of this Section 3.4 shall be deemed to include any legal or other
expenses reasonably incurred by such indemnified party in connection with
investigating or defending against any action or claim that is the subject of
this section. No person guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the 1933 Act) shall be entitled to contribution from
any person who was not guilty of such fraudulent misrepresentation. Any
obligation of a Holder to provide contribution will be individual to such Holder
and will be limited to the net amount of proceeds received by such Holder from
the sale of Registrable Stock that is the subject of any claim. No party shall
be liable for contribution with respect to any action, suit, proceeding or claim
settled without its written consent, which consent shall not be unreasonably
withheld, conditioned or delayed. The contribution obligation of any Holder will
be limited to the net amount of proceeds received by such Holder from the sale
of the Registrable Stock pursuant to such Registration Statement.

     3.5 Survival. The indemnification and contribution provided for under this
Agreement will remain in full force and effect regardless of any investigation
made by or on behalf of any indemnified party or any officer, director or
controlling Person of such indemnified party and will survive the transfer of
securities.

                                   ARTICLE 4

                                  MISCELLANEOUS

     4.1 Notices. All notices and other communications hereunder shall be in
writing and shall be delivered personally or by commercial delivery service, or
mailed by registered or certified mail (return receipt requested) or sent via
facsimile (with confirmation of receipt) to the parties at the following
addresses (or at such other address for a party as shall be specified by like
notice):

                          if to the Company, to:

                          The viaLink Company
                          13155 Noel Road, Suite 800
                          Dallas, Texas 75240
                          Attention: J. Andrew Kerner
                          Fax: (972) 934-5555

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                          with a copy (which shall not constitute notice) to:

                          Richard M. Klinge & Associates, P.C.
                          510 E. Memorial Road, Suite C-1
                          Oklahoma City, Oklahoma 73114
                          Attention: Richard M. Klinge, Esq.
                          Fax: (405) 775-9003

                          if to the Holder, at:

                          CT Corporation System
                          1209 Orange Street
                          Wilmington, Delaware 19801
                          Attention: Mark Ferrucci
                          Fax: (302) 658-2919

Notice given by personal delivery or commercial delivery service shall be
effective upon actual receipt. Notice given by mail shall be effective three
business days after deposit in the mails or upon actual receipt if sooner.
Notice given by facsimile shall be confirmed by appropriate answer back and
shall be effective upon actual receipt if received during the recipient's normal
business hours, or at the beginning of the recipient's next business day after
receipt if not received during the recipient's normal business hours.

     4.2 Interpretation. The words "include," "includes" and "including" when
used herein shall be deemed in each case to be followed by the words without
limitation. The headings contained in this Agreement are for reference purposes
only and shall not affect in any way the meaning or interpretation of this
Agreement.

     4.3 Counterparts. This Agreement may be executed in one or more
counterparts, all of which shall be considered one and the same agreement and
shall become effective when one or more counterparts have been signed by each of
the parties and delivered to the other parties, it being understood that all
parties need not sign the same counterpart.

     4.4 Entire Agreement. This Agreement constitutes the entire agreement among
the parties with respect to the subject matter hereof and supersedes all prior
agreements and understandings, both written and oral, among the parties with
respect to the subject matter hereof.

     4.5 Amendments and Waivers. Except as otherwise provided herein, no
amendment, modification, termination or cancellation of this Agreement shall be
effective as to (a) the Company, unless made in writing signed by the Company or
(b) the Holder, unless made in writing signed by the Holder.

     4.6 Successors and Assigns. This Agreement, and the rights and obligations
of a Holder hereunder, may be assigned by such Holder to any Person to which
Registrable Stock is transferred by such Holder and who agrees to be bound by
the terms of this Agreement. Any such transferee shall be deemed a "Holder" for
purposes of this Agreement; provided, that no

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transferee will be deemed to be a Holder unless such transferee is the holder of
not less than 50,000 shares of Registrable Stock.

     4.7 Severability. In the event that any provision of this Agreement, or the
application thereof, becomes or is declared by a court of competent jurisdiction
to be illegal, void or unenforceable, the remainder of this Agreement will
continue in full force and effect and the application of such provision to other
persons or circumstances will be interpreted so as reasonably to effect the
intent of the parties hereto. The parties further agree to replace such void or
unenforceable provision of this Agreement with a valid and enforceable provision
that will achieve, to the extent possible, the economic, business and other
purposes of such void or unenforceable provision.

     4.8 Remedies Cumulative. Except as otherwise provided herein, any and all
remedies herein expressly conferred upon a party will be deemed cumulative with
and not exclusive of any other remedy conferred hereby, or by law or equity upon
such party, and the exercise by a party of any one remedy will not preclude the
exercise of any other remedy. Each party hereto agrees to indemnify the other
against any and all loss, liability, expenses, damages, and/or fees (including
reasonable attorneys fees) arising out of such party's breach or non-performance
of any provision of this Agreement, and/or arising out of the enforcement of
this indemnity. In addition, the Company acknowledges that each Holder shall
have the right to have the provisions of this Agreement specifically enforced,
since there may not be an adequate remedy at law for non-performance.

     4.9 Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Texas (other than the conflicts of law
principles thereof) and shall, to the maximum extent practicable, be deemed to
call for performance in Dallas County, Texas.

     4.10 Rules of Construction. The parties hereto agree that they have been
represented by counsel during the negotiation, preparation and execution of this
Agreement and, therefore, waive the application of any law, regulation, holding
or rule of construction providing that ambiguities in an agreement or other
document will be construed against the party drafting such agreement or
document.

     4.11 Currency. All references to "$" or "dollars" herein shall be to the
lawful currency of United States dollars.

                            [Signature page follows.]

                                       11
<PAGE>   14

     IN WITNESS WHEREOF, the Company and the Holder have executed this
Registration Rights Agreement as of the date first written above.

                                          COMPANY:

                                          THE VIALINK COMPANY

                                          By: /s/ J. Andrew Kerner
                                              ---------------------------------
                                              J. Andrew Kerner
                                              Chief Financial Officer

                                          HOLDER:

                                          AGE INVESTMENTS, INC.

                                          By: /s/ Robert L. Proost
                                              ---------------------------------
                                              Name:  Robert L. Proost
                                              Title: Sole Director
                                                     Executed in St. Clair
                                                     County, IL<PAGE>   1
                                                                    EXHIBIT 10.2

                        ADDENDUM TO EMPLOYMENT AGREEMENT

         The Employment Agreement between The viaLink Company ("viaLink") and
J. Andrew Kerner dated the 1st day of April, 1999 is amended as follows:

1.   Effective as of the 10th day of March, 2000, the title of J. Andrew Kerner
     shall be "Senior Vice President of Finance and Chief Financial Officer".

2.   Effective as of the 10th day of March, 2000, the annualized salary set
     forth in Section 4.1 of said Employment Agreement shall be increased to
     Two Hundred and thirty eight thousand five hundred dollars ($238,500).

3.   The first sentence of Section 6.1 shall be deleted and replaced with the
     following sentence: "Except as hereinafter set forth, the term ("Term) of
     this Agreement shall commence on the 5th day of April, 1999 ("Effective
     Date and shall continue through the 25th day of May, 2001 and shall be
     automatically renewed on a year to year basis thereafter unless one party
     hereto notifies the other party hereto in writing at least thirty (30)
     days prior to the end of the then current Term that it will not renew this
     Agreement at the end of such then current Term."

4.   Except as amended herein, no further changes are made to the Employment
     Agreement and the same remains in full force and effect.

The viaLink Company                               J. Andrew Kerner

By:  /s/ LEWIS B. KILBOURNE                       /s/ J. ANDREW KERNER
     -------------------------                    ------------------------------
     Lewis B. Kilbourne                           J. Andrew Kerner

Its:   Chief Executive Officer

Date:  3/10/2000                                  Date: 3/14/00
     -------------------------                          ------------------------

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