<PAGE>

                                                                     Exhibit 4.5

THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED OR
OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT
OR PURSUANT TO RULE 144 OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
CORPORATION AND ITS COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED.

                           WARRANT TO PURCHASE STOCK

 Corporation:               Release Software Corporation, a Delaware Corporation
 Number of Shares:          35,714 (subject to Section 1.9)
 Class of Stock:            Series B Preferred (subject to Section 1.9)
 Initial Exercise Price:    $0.70 per share (subject to Section 1.9)
 Issue Date:                July 10, 1997
                                 --
 Expiration Date:           July 10, 2002 (Subject to Article 4.1)
                                 --

     THIS WARRANT CERTIFIES THAT, in consideration of the payment of $l.00 and
for other good and valuable consideration, IMPERIAL BANK or IMPERIAL BANCORP, at
their option, ("Holder") is entitled to purchase the number of fully paid and
nonassessable shares of the class of securities (the "Shares") of the
corporation (the "Company") at the initial exercise price per Share (the
"Warrant Price") all as set forth above and as adjusted pursuant to Article 2 of
this Warrant, subject to the provisions and upon the terms and conditions set
forth of this Warrant.

ARTICLE 1. EXERCISE
           --------

     1.1  Method of Exercise. Holder may exercise this Warrant by delivering
          ------------------
this Warrant and a duly executed Notice of Exercise in substantially the form
attached as Appendix 1 to the principal office of the Company. Unless Holder is
exercising the conversion right set forth in Section 1.2, Holder shall also
deliver to the Company a check for the aggregate Warrant Price for the Shares
being purchased.

     1.2  Conversion Right. In lieu of exercising this Warrant as specified in
          ----------------
Section 1.1, Holder may from time to time convert this Warrant, in whole or in
part, into a number of Shares determined by dividing (a) the aggregate fair
market value of the Shares or other securities otherwise issuable upon exercise
of this Warrant minus the aggregate Warrant Price of such Shares by (b) the fair
market value of one Share. The fair market value of the Shares shall be
determined pursuant to Section 1.5.

     1.3  Omitted.
          -------

     1.4  Omitted.
          -------

     1.5  Fair Market Value. If the Shares are traded regularly in a public
          -----------------
market, the fair market value of the Shares shall be the closing price of the
Shares (or the closing price of the Company's stock into which the Shares are
convertible) reported for the business day immediately before Holder delivers
<PAGE>

its Notice of Exercise to the Company. If the Shares are not regularly traded in
a public market, the Board of Directors of the Company shall determine fair
market value in its reasonable good faith judgment. The foregoing
notwithstanding, if Holder advises the Board of Directors in writing that Holder
disagrees with such determination, then the Company and Holder shall promptly
agree upon a reputable investment banking firm to undertake such valuation. If
the valuation of such investment banking firm is greater than that determined by
the Board of Directors, then all fees and expenses of such investment banking
firm shall be paid by the Company. In all other circumstances, such fees and
expenses shall be paid by Holder.

     1.6  Delivery of Certificate and New Warrant. Promptly after Holder
          ---------------------------------------
exercises or converts this Warrant, the Company shall deliver to Holder
certificates for the Shares acquired and, if this Warrant has not been fully
exercised or converted and has not expired, a new Warrant representing the
Shares not so acquired.

     1.7  Replacement of Warrants. On receipt of evidence reasonably
          -----------------------
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of loss, theft or destruction, on delivery of an
indemnity agreement reasonably satisfactory in form and amount to the Company
or, in the case of mutilation, or surrender and cancellation of this Warrant,
the Company at its expense shall execute and deliver, in lieu of this Warrant, a
new warrant of like tenor.

     1.8  Repurchase on Sale, Merger, or Consolidation of the Company.
          -----------------------------------------------------------

          1.8.1.    "Acquisition". For the purpose of this Warrant,
                     -----------
"Acquisition" means any sale, license, or other disposition of all or
substantially all of the assets (including intellectual property) of the
Company, or any reorganization, consolidation, or merger of the Company where
the holders of the Company's securities before the transaction beneficially own
less than 50% of the outstanding voting securities of the surviving entity after
the transaction.

          1.8.2.    Assumption of Warrant. If upon the closing of any
                    ---------------------
Acquisition the successor entity assumes the obligations of this Warrant, then
this Warrant shall be exercisable for the same securities, cash, and property as
would be payable for the Shares issuable upon exercise of the unexercised
portion of this Warrant as if such Shares were outstanding on the record date
for the Acquisition and subsequent closing. The Warrant Price shall be adjusted
accordingly. The Company shall use reasonable efforts to cause the surviving
corporation to assume the obligations of this Warrant.

          1.8.3.    Nonassumption. If upon the closing of any Acquisition the
                    -------------
successor entity does not assume the obligations of this Warrant and Holder has
not otherwise exercised this Warrant in full, then the unexercised portion of
this Warrant shall be deemed to have been automatically converted pursuant to
Section 1.2 and thereafter Holder shall participate in the Acquisition on the
same terms as other holders of the same class of securities of the Company.

          1.8.4.    Purchase Right. Notwithstanding the foregoing, at the
                    --------------
election of Holder, the Company shall purchase the unexercised portion of this
Warrant for cash upon the closing of any Acquisition for an amount equal to (a)
the fair market value of any consideration that would have been received by
Holder in consideration of the Shares had Holder exercised the unexercised
portion of this

                                       2
<PAGE>

Warrant immediately before the record date for determining the shareholders
entitled to participate in the proceeds of the Acquisition, less (b) the
aggregate Warrant Price of the Shares, but in no event less than zero; provided,
however, that the purchase right under this Section 1.8.4 shall not be effective
if the accountants for the Company determine that it would result in the
disallowance of pooling of interest treatment.

     1.9  Adjustment in Underlying Preferred Stock Price and Exercise Price.
          -----------------------------------------------------------------
If on or before August 15, 1997, the Company sells and issues to any investors,
preferred stock with aggregate gross proceeds to the Company of at least
$3,000,000, this Warrant shall concurrent with the issuance of such shares of
preferred stock automatically be adjusted to instead be exercisable for shares
of the same series and class and bearing the same rights, preferences, and
privileges, of such shares of stock, with the Warrant Price hereunder adjusted
to equal the per share purchase price of such stock, and the number of such
shares subject to this Warrant adjusted to equal (i) Twenty-Five Thousand
Dollars ($25,000.00), divided by (ii) such modified per share Warrant Price.

ARTICLE 2. ADJUSTMENTS TO THE SHARES.
           --------------------------

     2.1  Stock Dividends, Splits, Etc. If the Company declares or pays a
          ----------------------------
dividend on its common stock payable in common stock, or other securities,
subdivides the outstanding common stock into a greater amount of common stock,
then upon exercise of this Warrant, for each Share acquired, Holder shall
receive, without cost to Holder, the total number and kind of securities to
which Holder would have been entitled had Holder owned the Shares of record as
of the date the dividend or subdivision occurred.

     2.2  Reclassification, Exchange or Substitution. Upon any reclassification,
          ------------------------------------------
exchange, substitution, or other event that results in a change of the number
and/or class of the securities issuable upon exercise or conversion of this
Warrant, Holder shall be entitled to receive, upon exercise or conversion of
this Warrant, the number and kind of securities and property that Holder would
have received for the Shares if this Warrant had been exercised immediately
before such reclassification, exchange, substitution, or other event. Such an
event shall include any automatic conversion of the outstanding or issuable
securities of the Company of the same class or series as the Shares to common
stock pursuant to the terms of the Company's Articles of Incorporation upon the
closing of a registered public offering of the Company's common stock. The
Company or its successor shall promptly issue to Holder a new Warrant for such
new securities or other property. The new Warrant shall provide for adjustments
which shall be as nearly equivalent as may be practicable to the adjustments
provided for in this Article 2 including, without limitation, adjustments to the
Warrant Price and to the number of securities or property issuable upon exercise
of the new Warrant. The provisions of this Section 2.2 shall similarly apply to
successive reclassifications, exchanges, substitutions, or other events.

     2.3  Adjustments for Combinations, Etc. If the outstanding Shares are
          ---------------------------------
combined or consolidated, by reclassification or otherwise, into a lesser number
of shares, the Warrant Price shall be proportionately increased.

     2.4  Adjustments for Diluting Issuances. The Warrant Price and the number
          ----------------------------------
of Shares issuable upon exercise of this Warrant shall be subject to adjustment,
from time to time, in the manner set forth on Exhibit A, if attached, in the
event of Diluting Issuances (as defined on Exhibit A).

                                       3
<PAGE>

     2.5  No Impairment. The Company shall not, by amendment of its Articles of
          -------------
Incorporation or through a reorganization, transfer of assets, consolidation,
merger, dissolution, issue, or sale of securities or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed under this Warrant by the Company, but shall at all times
in good faith assist in carrying out all the provisions of this Article 2 and in
taking all such action as may be necessary or appropriate to protect Holder's
rights under this Article against impairment. If the Company takes any action
affecting the Shares or its common stock other than as described above that
adversely affects Holder's rights under this Warrant, the Warrant Price shall be
adjusted downward and the number of Shares issuable upon exercise of this
Warrant shall be adjusted upward in such a manner that the aggregate Warrant
Price of this Warrant is unchanged.

     2.6  Certificate as to Adjustments. Upon each adjustment of the Warrant
          -----------------------------
Price, the Company at its expense shall promptly compute such adjustment, and
furnish Holder with a certificate of its Chief Financial Officer setting forth
such adjustment and the facts upon which such adjustment is based. The Company
shall, upon written request, furnish Holder a certificate setting forth the
Warrant Price in effect upon the date thereof and the series of adjustments
leading to such Warrant Price.

ARTICLE 3. REPRESENTATIONS AND COVENANTS OF THE COMPANY.
           --------------------------------------------

     3.1  Representations and Warranties. The Company hereby represents and
          ------------------------------
warrants to the Holder as follows:

          (a)  The initial Warrant Price referenced on the first page of this
Warrant is not greater than the fair market value of the Shares as of the date
of this Warrant.

          (b)  All Shares which may be issued upon the exercise of the purchase
right represented by this Warrant, and all securities, if any, issuable upon
conversion of the Shares, shall, upon issuance, be duly authorized, validly
issued, fully paid and nonassessable, and free of any liens and encumbrances
except for restrictions on transfer provided for herein or under applicable
federal and state securities laws.

     3.2  Notice of Certain Events. If the Company proposes at any time (a) to
          ------------------------
declare any dividend or distribution upon its common stock, whether in cash,
property, stock, or other securities and whether or not a regular cash dividend;
(b) to offer for subscription pro rata to the holders of any class or series of
its stock any additional shares of stock of any class or series or other rights;
(c) to effect any reclassification or recapitalization of common stock; (d) to
merge or consolidate with or into any other corporation, or sell, lease,
license, or convey all or substantially all of its assets, or to liquidate,
dissolve or wind up; or (e) offer holders of registration rights the opportunity
to participate in an underwritten public offering of the company's securities
for cash, then, in connection with each such event, the Company shall give
Holder (1) at least 20 days prior written notice of the date on which a record
will be taken for such dividend, distribution, or subscription rights (and
specifying the date on which the holders of common stock will be entitled
thereto) or for determining rights to vote, if any, in respect of the matters
referred to in (c) and (d) above; (2) in the case of the matters referred to in
(c) and (d) above at least 20 days prior written notice of the date when the
same will take place (and specifying the date on which the holders of

                                       4
<PAGE>

common stock will be entitled to exchange their common stock for securities or
other property deliverable upon the occurrence of such event); and (3) in the
case of the matter referred to in (e) above, the same notice as is given to the
holders of such registration rights.

     3.3  Information Rights. So long as the Holder holds this Warrant and/or
          ------------------
any of the Shares, the Company shall deliver to the Holder (a) promptly after
mailing, copies of all communiques to the shareholders of the Company, (b)
within ninety (90) days after the end of each fiscal year of the Company, the
annual audited financial statements of the Company certified by independent
public accountants of recognized standing and (c) within forty-five (45) days
after the end of each of the first three quarters of each fiscal year, the
Company's quarterly, unaudited financial statements.

     3.4  Registration Under Securities Act of 1933, as amended. The Company
          -----------------------------------------------------
agrees that the Shares shall be subject to the registration rights set forth on
Exhibit B.

ARTICLE 4. MISCELLANEOUS.
           -------------

     4.1  Term: Notice of Expiration. This Warrant is exercisable, in whole or
          --------------------------
in part, at any time and from time to time on or before the Expiration Date set
forth above. The Company shall give Holder written notice of Holder's right to
exercise this Warrant in the form attached as Appendix 2 not more than 90 days
and not less than 30 days before the Expiration Date. If the notice is not so
given, the Expiration Date shall automatically be extended until 30 days after
the date the Company delivers the notice to Holder.

     4.2  Legends. This Warrant and the Shares (and the securities issuable,
          -------
directly or indirectly, upon conversion of the Shares, if any) shall be
imprinted with a legend in substantially the following form:

     THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
     AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED WITHOUT AN
     EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT OR PURSUANT TO RULE 144 OR
     AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE CORPORATION AND ITS
     COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED.

     4.3  Compliance with Securities Laws on Transfer. This Warrant and the
          -------------------------------------------
Shares issuable upon exercise this Warrant (and the securities issuable,
directly or indirectly, upon conversion of the Shares, if any) may not be
transferred or assigned in whole or in part without compliance with applicable
federal and state securities laws by the transferor and the transferee
(including, without limitation, the delivery of investment representation
letters and legal opinions reasonably satisfactory to the Company). The Company
shall not require Holder to provide an opinion of counsel if the transfer is to
an affiliate of Holder or if there is no material question as to the
availability of current information as referenced in Rule 144(c), Holder
represents that it has complied with Rule 144(d) and (e) in reasonable detail,
the selling broker represents that it has complied with Rule 144(f), and the
Company is provided with a copy of Holder's notice of proposed sale.

                                       5
<PAGE>

     4.4  Transfer Procedure. Subject to the provisions of Section 4.2. Holder
          ------------------
may transfer all or part of this Warrant or the Shares issuable upon exercise of
this Warrant (or the securities issuable, directly or indirectly, upon
conversion of the Shares, if any) by giving the Company notice of the portion of
the Warrant being transferred setting forth the name, address and taxpayer
identification number of the transferee and surrendering this Warrant to the
Company for reissuance to the transferee(s) (and Holder, if applicable). Unless
the Company is filing financial information with the SEC pursuant to the
Securities Exchange Act of 1934, the Company shall have the right to refuse to
transfer any portion of this Warrant to any person who directly competes with
the Company.

     4.5  Notices. All notices and other communications from the Company to the
          -------
Holder, or vice versa, shall be deemed delivered and effective when given
personally or mailed by first-class registered or certified mail, postage
prepaid, at such address as may have been furnished to the Company or the
Holder, as the case may be, in writing by the Company or such Holder from time
to time.

     4.6  Waiver. This Warrant and any term hereof may be changed, waived,
          ------
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.

     4.7  Attorneys' Fees. In the event of any dispute between the parties
          ---------------
concerning the terms and provisions of this Warrant, the party prevailing in
such dispute shall be entitled to collect from the other party all costs
incurred in such dispute, including reasonable attorneys' fees.

     4.8  Governing Law. This Warrant shall be governed by and construed in
          -------------
accordance with the laws of the State of California, without giving effect to
its principles regarding conflicts of law.

                                    Release Software Corporation

                                    By: /s/ Mark Benning
                                        ----------------------------

                                    Name: Mark Benning
                                          ----------------------------

                                    Title:            CFO
                                           ----------------------------

                                       6
<PAGE>

                                  APPENDIX 1

                              NOTICE OF EXERCISE
                              ------------------

     1.   The undersigned hereby elects to purchase ________ shares of the
Series B Preferred Stock of Release Software Corporation pursuant to the terms
of the attached Warrant, and tenders herewith payment of the purchase price of
such shares in full.

     1.   The undersigned hereby elects to convert the attached Warrant into
Shares/cash [strike one] in the manner specified in the Warrant. This conversion
is exercised with respect to ____________ of the Shares covered by the Warrant.

     [Strike paragraph that does not apply.]

     2.   Please issue a certificate or certificates representing said shares in
the name of the undersigned or in such other name as is specified below:

               Christine McCarthy
               Chief Financial Officer
               Controllers Department
               Imperial Bank or Imperial Bancorp
               P.O. Box 92991
               Los Angeles, CA 90009


     3.   The undersigned represents it is acquiring the shares solely for its
own account and not as a nominee for any other party and not with a view toward
the resale or distribution thereof except in compliance with applicable
securities laws.

IMPERIAL BANK or IMPERIAL BANCORP


_________________________________
(Signature)

_________________________________
(Date)

                                       7
<PAGE>

                                  APPENDIX 2

                    NOTICE THAT WARRANT IS ABOUT TO EXPIRE
                    --------------------------------------


____________, ____



Christine McCarthy
Chief Financial Officer
Controllers Department
Imperial Bank or Imperial Bancorp
P.O. Box 92991
Los Angeles, CA 90009

Dear Christine:

This is to advise you that the Warrant issued to you described below will expire
on July 10, 2002.
        --

Issuer:                            Release Software Corporation

Issue Date:                        July 10, 1997
                                        --

Class of Security Issuable:        Series B Preferred (Subject to Section 1.9)

Exercise Price Per Share:          $0.70 (Subject to Section 1.9)

Number of Shares Issuable:         35,714 (Subject to Section 1.9)

Procedure for Exercise:

Please contact [name of contact person at (phone number)] with any questions you
may have concerning exercise of the Warrant. This is your only notice of pending
expiration.

RELEASE SOFTWARE CORPORATION

By:   ________________________

Its:  ________________________

                                       8
<PAGE>

                                   EXHIBIT A
                                   ---------

                           Anti-Dilution Provisions
                           ------------------------

     In the event of the issuance (a "Diluting Issuance") by the Company, after
the Issue Date of the Warrant, of securities at a price per share less than the
Warrant Price, then the number of shares of common stock issuable upon
conversion of the Shares shall be adjusted in accordance with those provisions
(the "Provisions") of the Company's Articles (Certificate) of Incorporation
which apply to Diluting Issuances.

     Under no circumstances shall the aggregate Warrant Price payable by the
Holder upon exercise of the Warrant increase as a result of any adjustment
arising from a Diluting Issuance.

                                       9
<PAGE>

                                   EXHIBIT B
                                   ---------

                              Registration Rights
                              -------------------


     The Shares shall be deemed "registrable securities" or otherwise entitled
to "piggy back" registration rights in accordance with the terms of the
following agreement (the "Agreement") between the Company and its investor(s):


          Investors' Rights Agreement dated July     , 1997
          -------------------------------------------------


The Company represents and warrants that all consents necessary to make Holder a
party to the Agreement have been obtained.

                                      10