<PAGE>   1
                                  EXHIBIT A

                                                              EXHIBIT 10.14

                             ASSIGNMENT OF LEASE


        THIS ASSIGNMENT is executed as of this 21st day of April, 1998, 
by INTRANET INTEGRATION GROUP, INC., a Minnesota corporation ("Assignor"), in
favor of DIGITAL RIVER, INC., a Delaware corporation ("Assignee").


                                   RECITALS

        Assignor, as Tenant, and CSM Investors, Inc., a Minnesota
        corporation, as Landlord ("Landlord") entered into that certain Leases
        ("the Lease") dated April 24, 1996 regarding 32,919 square feet of
        space in the Golden Triangle Business Center, located at 9625-9675 West
        76th Street, Eden Prairie, Minnesota (the "Premises").
        
        Assignor desires to sell, transfer, convey and assign to
        Assignee, and Assignee desires to acquire and assume Assignor's
        interest in the Lease, according to the terms and conditions set forth
        hereinbelow.
        
           NOW, THEREFORE, in consideration of the mutual promises herein and 
other good and valuable consideration, the receipt and sufficiency of
which is hereby acknowledged by both parties, Assignor and Assignee agree as
follows:

        1.)   Recitals.  The foregoing recitals are correct and are incorporated
herein.

        2.)   Assignment and Assumption.  As of the Effective Date (defined
below): (i) Assignor hereby assigns, transfers and conveys the Tenant's
interest in the Lease to Assignee and (ii) Assignee hereby assumes and agrees
to perform all of the obligations of the Tenant under the Lease that arise from
and after the Effective Date hereof in accordance with the terms and conditions
set forth in the Lease.

        3.)   Representations and Warranties.  Assignor represents and warrants
to Assignee as follows:

        (a)   A true and complete copy of the Lease is attached hereto as 
        Exhibit A and it is the only instrument and agreement in effect
        between Landlord and Assignor.  The Lease contains the entire
        agreement between Landlord and Assignor concerning the Premises. The
        Lease is in full force and effect and has not in any way been
        modified, amended, terminated or rescinded.
        
        (b)   To the best of Assignor's knowledge, there exists no default nor
        any event that, with the passing of time or delivery of notice or
        both, would constitute a default under the Lease.
        











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        (c)     Rent and all other amounts due and payable by Assignor under
        the Lease (collectively, the "Rent") are current and no Rent or
        other amount is presently due and payable by Assignor to Landlord,
        including any retroactive adjustments to Rent.

        (d)     Assignor has not issued or received any notice of cancellation, 
        termination or any other document affecting the Lease in any way, and
        has no knowledge of any violation of any governmental statute,
        regulation or ordinance relating to the Premises or the Lease.

        (e)     Assignor has good right to assign and transfer the Lease
        (subject to obtaining the Consent of Landlord).  The Lease is free
        and clear of all charges and encumbrances.

        (f)     Assignor has received no notice of actual or threatened
        reduction or curtailment of any utility service supplied to the
        Premises, nor of any action or proceeding in condemnation, eminent
        domain, or foreclosure in connection with or relating to the Premises.

        (g)     Assignor has not notice of any actual or threatened cancellation
        or suspension of any certificates of occupancy for all or any portion
        of the Premises.

        (h)     Assignor is not in default in any of its legal obligations or   
        liabilities regarding the Premises.

        (i)     To the best of Assignor's knowledge, Assignor's current use of
        the Premises does not violate any federal, state, local or other
        governmental building, zoning, health, accessibility, safety, planning,
        subdivision, or other law, ordinance, or regulation, or any applicable
        private restriction, and such use is a legal conforming use.

        (j)     Assignor has not received any notice of, nor is Assignor aware
        of, any action, litigation, investigation, condemnation, violation, or
        proceeding of any kind from any federal, state or local government
        entity against Assignor relating to any portion of the Premises.

        (k)     Assignor is not aware of any defects in the structures or other 
        improvements on the Premises, including but without limitation the
        roof, fixtures, systems or structure of such improvements.

Assignee is relying on the accuracy of the foregoing representations and
warranties in entering into this Agreement.  The foregoing representations and
warranties are a material inducement to Assignee to enter into this Agreement.

        4.)     Effective Date.  The Effective Date of this Assignment shall be 
July 15, 1998, or such earlier date as may be mutually agreed by Assignor and 
Assignee.

        5.)     Delivery of Occupancy

        (a)     As of May 1, 1998, Assignee shall have access to approximately
        1,500 square feet of the Premises as shown cross-hatched on the plan
        attached hereto as Exhibit B (the

                                      2.

<PAGE>   3
        "Partial Premises").  Assignee shall pay rent Assignor in the amount of
        Three Thousand and no/100 Dollars ($3,000.00) in consideration for such
        early occupancy, which amount shall be due and payable on or before May
        1, 1998 and shall be considered gross rent, inclusive of all base rent,
        additional rent, operating costs, real estate taxes, utility costs and
        all other charges, fees, costs and expenses.  Prior to May 1, 1998,
        Assignor shall remove all personal property and all other items from
        the Partial Premises and shall deliver the Partial Premises in
        broom/vacuum clean condition, at Assignor's expense.
        
        (b)     Assignee shall pay all costs and expenses in connection with
        setting up the Partial Premises for Assignee's use.

        (c)     During said early occupancy of the Partial Premises, Assignor
        will make available to Assignee 20 of 24 frames on one of its T-1
        Lines.  Assignee will work with the MIS Director of Assignor on
        accessing such line to not disrupt Assignor's systems.  Any costs
        associated with activating such T-1 Line shall be at the cost of
        Assignee and Assignee further agrees to diligently work toward its own
        T-1 Line in a reasonable and timely fashion.
        
        (d)     On the Effective Date, assignor shall deliver all of the
        Premises to Assignee in broom/vacuum clean condition.  If such
        occupancy commences on a date other than the first of a calendar month,
        then base rent, additional rent and other charges under the Lease, and
        any other operating expenses in connection with the Premises, shall be
        prorated between Assignor and Assignee as of the date of such
        occupancy.
        
        (e)     The raised floor production area within the Premises shall
        remain intact and shall not be altered by Assignor.  Without
        limitation, the raised floor, air conditioning equipment and fixtures,
        and fire safety equipment and systems shall not be removed or altered
        by Assignor.  However, Assignor shall remove its computer equipment and
        personal property.

        6.)     HVAC Certification.  Prior to the Effective Date, Assignor
shall deliver to Assignee a certification from a licensed, bonded and insured
HVAC contractor that all heating, ventilating and air conditioning equipment
serving the Premises is in proper working order.

        7.)     Security Deposit.  Prior to the execution of the Agreement,
Assignee deposited with Assignor the sum of Twenty Thousand and no/100 Dollars
($20,000.00).  Contemporaneously with the execution of this Assignment,
Assignee has deposited with Assignor an additional sum of Eleven Thousand and
no/100 Dollers ($11,000.00).  Said total of Thirty-one Thousand and no/100
Dollars ($31,000.00) shall be a security deposit for the performance by
Assignee of the terms and covenants of the Lease hereby assumed by Assignee. 
If Assignee fails to keep and perform the terms and covenants of the Lease
assumed by Assignee and Assignor incurs loss or damage as a result of Landlord
pursuing such payment or performance from Assignor, then Assignor, then
Assignor shall have the right to apply such portion of said deposit as may be
necessary to reimburse Assignor for such loss or damage sustained.  Said
deposit shall be returned to Assignee, less any depletion thereof as a result
of the provisions of



                                      3.

<PAGE>   4
this paragraph, upon the expiration or termination of the Lease.  If, at any
time prior to the expiration or termination of the Lease, Assignor is released
from liability under the Lease, then the entire deposit shall be promptly
returned to Assignee.

        8.)  Miscellaneous.  The heading used herein are for convenience only
and are not to be used in interpreting this Agreement.  This Agreement shall be
construed, enforced and interpreted under the laws of the State of Minnesota. 
This Agreement is the entire agreement between Assignor and Assignee regarding
the subject matter hereof; any prior agreements are superseded hereby.  This
Agreement may not be modified, amended or changed orally, but only by an
agreement in writing signed by the parties hereto.  Neither party shall be
deemed to have waived any rights under this Agreement unless such waiver is
given in writing and signed by such party.  If any provision of this Agreement
is invalid or unenforceable, such provision shall be deemed to be modified to
be within the limits of enforceability or validity, if feasible; however, if
the offending provision cannot be so modified, it shall be stricken and all
other provisions of this Agreement in all other respects shall remain valid and
enforceable.  In the event of a breach or default under this Agreement, the
non-defaulting party shall be entitled to recover reasonable attorneys' fees
and court cost incurred to enforce its rights regarding such default or breach.

        IN WITNESS WHEREOF, the parties hereto have executed this Assignment of
Lease of the day and year first above written.

                                                ASSIGNOR:
                                                INTRANET INTEGRATION GROUP,
                                                INC.

Dated:       4-21-98                            By:    [SIG]
      -----------------------                      ---------------------------
                                                   Its:  CEO


                                                ASSIGNEE:
                                                DIGITAL RIVER, INC.



Dated:       4-21-98                            By:    [SIG]
      -----------------------                      ---------------------------
                                                   Its:  President












                                      4
<PAGE>   5
                CONSENT TO ASSIGNMENT AND ASSUMPTION OF LEASE


THIS CONSENT TO ASSIGNMENT AND ASSUMPTION OF LEASE ("Consent") is into efective
as of APRIL 22, 1998 ("Effective Date").  by CSM INVESTORS, INC., a Minnesota
corporation ("Landlord"), in favor of INTRANET INTEGRATION GROUP, INC., a
Minnesota corporation d/b/a Technical Publishing Solutions, Inc.  ("Assignor")
and DIGITAL RIVER, INC., a Delaware corporation ("Assignee").


                                   RECITALS


        A.      Landlord and Assignor, as the Tenant, are parties to that
certain lease dated April 24, 1996 (the "Lease") whereby landlord leases to
Assignor the premises ("Premises") consisting of approximately 32,919 square
feet of area in the Golden Triangle Business Center located at 9625-9675 West
76th Street, Eden Prairie, Minnesota (the "Project"), as more fully described
in the Lease.

        B.      Assignor and Assignee have executed that certain Assignment of
Lease dated April 21, 1998 with an effective date of July 15, 1998 (the
"Effective Date"), a true and correct copy of which is attached hereto as
EXHIBIT A (the "Assignment") whereby Assignor has assigned to Assignee, and
Assignee has assumed, all of Assignor's right, title, interest and obligations
in, to and under the Lease, subject to the covenants, terms and conditions set
forth therein.

        C.      As a condition of the Assignment, Assignor and Assignee have
requested that Landlord consent to and approve of the Assignment.

        D.      Landlord is willing to do so conditioned upon and subject to
the terms and conditions set forth herein.

NOW THEREFORE, FOR GOOD AND VALUABLE CONSIDERATION, the receipt and sufficiency 
of which are hereby acknowledged, Landlord hereby agrees as follows:

                                   CONSENT

        1.      Landlord hereby consents to and approves of the Assignment,
subject to the terms hereof.

        2.      Notwithstanding Landlord's consent to the Assignment, Landlord
does not agree to and nothing contained herein or in the Assignment shall be
construed as a release of Assignor from its obligations, covenants, duties and
liabilities under the Lease monetary or otherwise.

        3.      Assignor and Assignee agree that Assignee shall be responsible
for any sums owing Landlord, or shall receive the benefit of any sums due from
landlord, if any, derived from Landlor's annual reconciliation of Operation
Expenses incurred in the year 1998, to be performed in accordance with the
Lease in the year 1999.

        4.      Landlord consents and agrees to the following:

                a.      Notice Address:  From and after the Effective Date, the 
                        address for notices to the Tenant under Section 14.5 of
                        the Lease shall be as follows:

                        DIGITAL RIVER, INC.
                        9625 W. 76TH STREET
                        SUITE 150
                        EDEN PRAIRIE, MN  55344
                        ATTN:  JOEL A. RONNING

                b.      Improvements.  Landlord consents to Assignee making the 
                        alterations and improvements described and/or shown in 
                        the attached EXHIBIT B (the "Work").  The Work shall be





<PAGE>   6
                     performed at Assignee's sole cost and expense by 
                     licensed and insured contractors and in accordance
                     with all of the requirements, terms and conditions of
                     the Lease, including without limitation, Section 6.2 of
                     the Lease.
             
             c.      Permitted Use.  Landlord agrees that the permitted
                     uses under Section 1.5 shall include the sale of
                     products by internet commerce, including but not
                     limited to software and digital products.
             
             d.      Signage.  Landlord consents to changing the
                     name of the business operating at the Premises to
                     "Digital River, Inc." or upon request of Assignee, a 
                     substantially similar name, and subject to the terms of
                     Section 3.2 and Exhibit D of the Lease, to a change in
                     the signage for the Premises to reflect the name change.
             
        5.   Except as specifically provided herein, nothing contained in this 
Consent shall be construed to modify or alter any of the terms, covenants or
conditions of the Lease and the Lease shall remain in full force and effect.

        6.   Nothing contained in this consent to any future assignment or
sublease of all or any portion of the Premises by either Assignor or Assignee.

        7.   This Consent may be executed in any number of counterparts,
each of which when so executed and delivered shall be deemed an original, but 
together shall constitute one and the same instrument.

        8.   This Consent is expressly conditioned upon execution of this 
Consent by Landlord's mortgage lender for the Project, USG Annuity & Life 
Company, and if this Consent is not so executed, both the Assignment and this 
Consent shall be null and void and of no effect.

IN WITNESS WHEREOF, Landlord has executed this Consent effective as of the day
and year first above written.

LANDLORD:

CSM INVESTORS, INC.,
a Minnesota corporation
                              REVIEWED
BY: [SIG]                     BY DJY
  -----------------------

Title: V.P.                   DATE
      ---------------------      4/23/98



                              CONSENT OF LENDER

The undersigned, being the present holder of an Assignment of Rents and Leases
dated September 5, 1996 executed by CSM Investors, Inc. in favor of the
undersigned, relative to the project commonly known as the Golden Triangle
Business Center located in Eden Prairie, Minnesota, hereby consents to the
above described Assignment, subject to and conditioned upon the same terms and
conditions as set forth hereinabove for Landlord's consent.

Dated: May 4, 1998                       USG ANNUITY & LIFE COMPANY,
     ---------------------               an Oklahoma corporation

                                         By USG INVESTMENT MANAGEMENT LLC,
                                         its authorized representative
                                         By: Daniel J. Foley
                                           ----------------------
                                           Daniel J. Foley
                                         Its: Vice President
                                            ---------------------