<PAGE>

                                                                     EXHIBIT 4.5

          THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
     UNDER THE SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE OFFERED, SOLD
     OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
     REGISTERED UNDER THE ACT OR, IN THE OPINION OF COUNSEL IN FORM AND
     SUBSTANCE SATISFACTORY TO THE COMPANY, SUCH OFFER, SALE OR TRANSFER, PLEDGE
     OR HYPOTHECATION IS IN COMPLIANCE THEREWITH.



                       SERIES E PREFERRED STOCK WARRANT

                                      of

                          TERRAPIN TECHNOLOGIES, INC.


    THIS CERTIFIES THAT GLEN McLAUGHLIN ("Warrantholder") is entitled to
subscribe for and purchase from TERRAPIN TECHNOLOGIES, INC., a Delaware
corporation (the "Company") 176 fully-paid and non-assessable shares of the
Company's Series E Preferred Stock (the "Preferred"), at a price of $50.00 per
share (the "Warrant Price"), such price and such number of shares being subject
to adjustment upon the occurrence of the contingencies set forth in this
Warrant. As of the date hereof, each share of Series E Preferred is convertible
into 66-2/3 shares of Common stock. This Warrant is granted in connection with
the extension of a loan against certain equipment pursuant to that certain
Master Loan Agreement by and between the Company and Venture Leasing Associates
dated December 31, 1992.

    Upon delivery of this Warrant, together with payment of the Warrant Price of
the shares of the Preferred thereby purchased, at the principal office of the
Company or at such other office or agency as the Company may designate by notice
in writing to the holder hereof, the holder of this Warrant shall be entitled to
receive a certificate or certificates for the shares of Preferred so purchased.
The date at which the Company receives (i) the Warrant and (ii) payment for the
shares of Preferred, either by payment in cash or by check, or by notice of the
Warrantholder's intent to use the proceeds from the sale of shares at a Public
Offering (as defined below), if any, or notice of intent to use shares of
Preferred as payment, both as described in Section 1 below, or such later date
as such notice shall specify, shall be referred to herein as the "Exercise
Date." All shares of Preferred which may be issued upon the exercise of this
Warrant will, upon issuance, be fully paid and non-assessable and free from all
taxes, liens and charges with respect to the issue thereof.

    This Warrant is subject to the following terms and conditions:

    1.   Exercise of Warrant: This Warrant may be exercised in whole or in part,
         -------------------
at any time on or before the earlier of (i) December 31, 2002, (ii)
consolidation or merger of the Company in which the shareholders of the Company
do not own a majority of the combined voting power of the surviving corporation
or its parent after such consolidation or merger, and (iii) the closing of an
underwritten public offering (a "Public Offering") of the Company's equity
securities pursuant to a registration statement under the Securities Act of
1933, as amended (the "Act"), by the surrender of this Warrant at the principal
office of the Company and by the payment to the Company, in the manner provided
for in the following paragraph, of the Warrant Price for all of the Preferred
purchased. The Company shall, within 20 days after such delivery, prepare a
certificate for the shares of Preferred purchased in the name of the holder of
this Warrant, or as such holder may direct (subject to the restrictions upon
transfer contained herein and upon payment by such holder
<PAGE>

hereof of any applicable transfer taxes).

        This Warrant may be exercised by the payment to the Company, by cash or
check, or from the proceeds of the sale of shares of Common Stock issued upon
conversion of shares of Preferred issued upon exercise of this Warrant sold by
the Warrantholder pursuant to a Public Offering of an amount equal to the
aggregate Warrant Price of the shares being purchased, if the Warrantholder
shall so participate in a Public Offering. The rights of the Warrantholder, to
so participate, shall be governed by the Registration Rights Agreement (as
hereinafter defined) and not this Warrant.  In lieu of exercising this Warrant
as described above, the Warrantholder may elect to receive shares equal to the
value (as determined below) of this Warrant (or the portion thereof being
cancelled) by surrender of this Warrant at the principal office of the Company
together with notice of such election (which notice shall include the number of
shares being exercised hereunder), in which event the Company shall issue to the
Warrantholder a number of shares of Preferred equal to the quotient obtained by
dividing (x) the value of the shares of Preferred being exercised (the
"Exercised Shares") on the Exercise Date, which value shall be determined by
subtracting (A) the aggregate Warrant Price of the Exercised Shares immediately
prior to the exercise of the Warrant from (B) the aggregate fair market value of
the Exercised Shares on the Exercise Date by (y) the fair market value of one
share of Preferred (or Common Stock if the Preferred has been converted into
Common Stock) as of the Exercise Date. No fractional shares shall be issuable
upon exercise of this Warrant, and if the number of shares to be issued
determined in accordance with the foregoing formula is other than a whole
number, the Company shall pay to the Warrantholder an amount in cash equal to
the fair market value of the resulting fractional share on the Exercise Date.

        The exercise of this Warrant may be made contingent upon (i) the closing
of a Public Offering, (ii) the closing of any consolidation or merger which
would trigger termination of the Warrant under clause (ii) of the first
paragraph of this section 1, or  (iii) the sale of all or substantially all of
the assets of the Company. The Company shall notify the holder if an event or
transaction of the kind described in this section is proposed at least fifteen
days prior to the closing of such event or transaction; such notice shall also
contain such details of the proposed event or transaction as are reasonable in
the circumstances and notice that this Warrant shall expire upon the closing
thereof. The information contained in such notice shall be kept confidential by
the Warrantholder until a public announcement of such information has occurred.

        Certificates for the shares issuable upon exercise of this Warrant and,
if applicable, a new warrant evidencing the balance of the shares remaining
subject to this Warrant shall be issued as of the Exercise Date and shall be
delivered to the holder within thirty days following the Exercise Date.

        For purposes of this Section 1, the fair market value of the Preferred
shall be determined as follows:

        (i)   If this Warrant is exercised in connection with and contingent
upon a Public Offering, and if the Company's registration statement relating to
such Public Offering has been declared effective by the Securities and Exchange
Commission, then the fair market value shall be the initial "Price to Public"
specified in the final prospectus with respect to such offering.

        (ii)  If this Warrant is not exercised in connection with and contingent
upon a Public Offering, then the fair market value shall be determined in good
faith by the Company's Board of Directors.

    2.  Transfer of Warrant.  Except in accordance with the conditions contained
        -------------------
in Section 3 hereof, this Warrant and all rights hereunder are not transferable.

    3.  Condition of Transfer or Exercise of Warrant. It shall be a condition to
        --------------------------------------------
any transfer or exercise
<PAGE>

of this Warrant that the Company shall have received, at the time of such
transfer or exercise, a representation in writing that this Warrant (or portion
hereof transferred) or the shares of Preferred being issued upon such exercise,
as the case may be, are being acquired for investment not with a view to any
sale or distribution thereof, or a statement of the pertinent facts covering any
proposed distribution thereof. It shall be a further condition to any transfer
of this Warrant or of any or all of the shares of Preferred issued upon exercise
of this Warrant, or Common Stock issued upon conversion of the Preferred, other
than a transfer registered under the Act, that the Company shall have received a
legal opinion, in form and substance satisfactory to the Company and its
counsel, reciting the pertinent circumstances surrounding the proposed transfer
and stating that such transfer is exempt from the prospectus and the
registration requirements of the Act. The requirement of a legal opinion shall
not apply to the transfer of this Warrant or any part thereof to a partnership
of which the Warrantholder is a partner or to the beneficial owners of such
partnership without further consideration, so long as such transfer is in
compliance with applicable securities laws. Each certificate evidencing the
shares of Preferred issued upon exercise of this Warrant, or Common Stock issued
upon conversion of the Preferred, or upon any transfer of such shares (other
than a transfer registered under the Act or any subsequent transfer or shares so
registered) shall, at the option of the Company, contain a legend, in form and
substance satisfactory to the Company and its counsel, restricting the transfer
of such shares to sales or other dispositions exempt from the requirements of
the Act.

        It shall be a further condition to each such transfer that the
transferee shall receive and accept a Warrant, of like tenor and date, executed
by the Company.

    4.  Adjustment of Warrant Price and Number of Shares Purchasable Hereunder.
        ----------------------------------------------------------------------
The Warrant Price and the number of shares purchasable hereunder shall be
subject to adjustment from time to time in accordance with the following
provisions, provided, however, that no such adjustment shall be made if a
corresponding adjustment is made to the "Conversion Price" of the Preferred in
the Company's Certificate of Incorporation, as amended:

        (a)  Subdivisions.   In case the Company shall at any time subdivide the
             ------------
outstanding shares of its Preferred Stock, the Warrant Price in effect
immediately prior to such subdivision shall be proportionately decreased, and in
case the Company shall at any time combine the outstanding shares of its
Preferred Stock, the Warrant Price in effect immediately prior to such
combination shall be proportionately increased, effective at the close of
business on the date of such subdivision or combination, as the case may be.

        (b) Stock Dividends. In case the Company shall at any time pay a
            ---------------
dividend with respect to Preferred payable in Preferred, then the Warrant Price
in effect immediately prior to the record date for distribution of such dividend
shall be adjusted to that price determined by multiplying the Warrant Price in
effect immediately prior to such record date by a fraction (i) the numerator of
which shall be the total number of shares of Preferred outstanding immediately
prior to such dividend and (ii) the denominator of which shall be the total
number of shares of Preferred outstanding immediately after such dividend.

        (c) Number of Shares. Upon each adjustment pursuant to subdivisions (a)
            ----------------
or (b) of this Section 4, the registered holder of this Warrant shall thereafter
(until another such adjustment) be entitled to purchase, at the adjusted Warrant
Price, the number of shares of Preferred, calculated to the nearest full share,
obtained by multiplying the number of shares of Preferred purchasable hereunder
immediately prior to such adjustment by the Warrant Price in effect prior to
such adjustment and dividing the product so obtained by the adjusted Warrant
price.

        (d) Reclassification or Merger.  In case of any reclassification, change
            --------------------------
or conversion of securities of the class or series issuable upon exercise of
this Warrant (other than as a result of a subdivision or combination described
above), the Company, or such successor or purchasing corporation,

                                       2
<PAGE>

as the case may be, shall duly execute and deliver to the Warrantholder a new
warrant so that the Warrantholder shall have the right to receive, at a total
purchase price not to exceed that payable upon the exercise of the unexercised
portion of this Warrant, and in lieu of the shares of Preferred theretofore
issuable upon exercise of this Warrant, the kind and amount of shares of stock,
other securities, money and property receivable upon such reclassification,
change or merger by a holder of the number of shares of Preferred then
purchasable under this Warrant. Such new warrant shall provide for adjustments
that shall be as nearly equivalent as may be practicable to the adjustments
provided for in this Section 4. The provisions of this subparagraph (d) shall
similarly apply to successive reclassifications, changes, and mergers.

        (e) Antidilution Rights. The other antidilution rights applicable to the
            -------------------
Preferred and the Common Stock of the Company are set forth in the Certificate
of Incorporation (the "Certificate"), as amended from time to time, a true and
complete copy in its current form which is attached hereto as Exhibit A. The
Company shall promptly provide the Warrantholder hereof with any restatement,
amendment or modification to the Certificate promptly after the same has been
made.

    5.  Notices.
        -------

        (a) Upon any adjustment of the Warrant Price and any increase or
decrease in the number of shares of Preferred purchasable upon the exercise of
this Warrant, then, and in each such case, the Company, within thirty (30) days
thereafter, shall give written notice thereof to the registered holder of this
Warrant at the address of such holder as shown on the books of the Company which
notice shall state the Warrant Price as adjusted and the
<PAGE>

increased or decreased number of shares purchasable upon the exercise of this
Warrant, setting forth in reasonable detail the method of calculation of each.

        (b) In the event that the Company shall propose at any time to effect: a
public offering of the Company's Common Stock pursuant to an effective
registration statement under the Act, the Company shall send to the
Warrantholder at least twenty days' prior written notice of the date when the
same is anticipated to take place; provided, however, that the failure to give
such notice shall not give the Warrantholder the right to delay or otherwise
restrain or affect the Public Offering. Such written notice shall be given by
first class mail, postage prepaid, addressed to the Warrantholder at the address
as shown on the books of the Company for the Warrantholder.

    6.  Registration. The Warrantholder shall be a "Holder" and the shares of
        ------------
Common Stock issuable upon conversion of the Preferred issuable upon exercise of
this Warrant shall be Registrable Securities" under that certain Investor Rights
Agreement by and among the Company and the other parties thereto dated as of
December 3, 1992 (the "Registration Rights Agreement"). Waiver, termination,
and amendment of the Registration Rights Agreement shall be controlled by the
provisions thereof, without regard to this Warrant.

    7.  Representations of Warrantholder. Concurrently with the receipt of this
        --------------------------------
Warrant, the Warrantholder shall have executed the Investment Representation
Statement in the form attached hereto as Exhibit B.

    8.  Representations and Warranties of the Company.
        ---------------------------------------------

        The Company represents and warrants to the Warrantholder as follows:

        (a) This Warrant has been duly authorized and executed by the Company
and is a valid and binding obligation of the Company, enforceable in accordance
with its terms except as to (i) the effect of applicable bankruptcy and similar
laws affecting the rights of creditors, and (ii) the effect of rules of law
governing specific performance, injunctive relief and other equitable remedies.

        (b) The Preferred has been duly authorized and reserved for issuance by
the Company and, when issued in accordance with the terms hereof, will be
validly issued, fully paid and non-assessable, and free from all taxes, liens
and changes with respect to the issues of such shares.

        (c) The rights, preference, privileges and restrictions granted to or
imposed upon the Preferred and the holders thereof are as set forth in the
Company's Certificate of Incorporation as amended, a true and complete copy of
which has been delivered to the Warrantholder.

        (d) The execution and delivery of this Warrant is not, and the issuance
of the Preferred upon exercise of this Warrant in accordance with the terms
hereof is not, inconsistent with the Company's Certificate of Incorporation or
Bylaws, does not contravene any law, governmental rule or regulation, judgment
or order applicable to the Company, and does not conflict with or contravene any
provision of, or constitute a default under, any indenture, mortgage, contract
or other instrument of which the Company is a party or by which it is bound or
require the consent or approval of, the giving of notice to, the registration or
filing with or the taking of any action in respect of or by, any federal, state
or local government authority or agency or other person, other than state or
federal securities law filings.
<PAGE>

        (e) During the period within which this Warrant may be exercised, the
Company will at all times have authorized and reserved for the purpose of the
issue upon exercise of this Warrant a sufficient number of shares of its
Preferred to provide for the exercise of this Warrant and a sufficient number of
shares of its Common Stock to provide for the conversion of the Preferred into
Common Stock.

    9.  Miscellaneous.
        -------------

        (a) The terms of this Warrant shall be binding upon and shall inure to
the benefit of any successors or assigns of the Company and of the holder or
holders hereof and of the Preferred issued or issuable upon the exercise hereof,
and all of the obligations of the Company relating to the Preferred issuable
upon exercise of this Warrant shall survive the exercise of this Warrant.

        (b) No holder of this Warrant, as such, shall be entitled to vote or
receive dividends or be deemed to be a shareholder of the Company for any
purpose, nor shall anything contained in this Warrant be construed to confer
upon the holder of this Warrant, as such, any rights of a shareholder of the
Company or any right to vote, give or withhold consent to any corporate action,
receive notice of meetings, receive dividends or subscription rights, or
otherwise.

        (c) Receipt of this Warrant by the holder hereof shall constitute
acceptance of and agreement to the foregoing terms and conditions.

        (d) The Company will not, by amendment of its Certificate of
Incorporation or through any other means, avoid or seek to avoid the observance
or performance of any of the terms of this Warrant, but will at all times in
good faith assist in the carrying out of all such terms and in the taking of all
such action as may be necessary or appropriate in order to protect the rights of
the holder of this Warrant against impairment.

        (e) Upon receipt of evidence reasonably satisfactory to the Company of
the loss, theft, destruction or mutilation of this Warrant and, in the case of
any such loss, theft or destruction, upon delivery of an indemnity agreement
reasonably satisfactory in form and amount to the Company, or in the case of any
such mutilation, upon surrender and cancellation of such Warrant, the Company
will execute and deliver, in lieu thereof, a new Warrant of like date and tenor.

        (f) This Warrant shall be governed by, construed and enforced in
accordance with the laws of the State of California, as applied to agreements
made and performed in California by residents of the State of California.

        (g) So long as this Warrant has not terminated, the Warrantholder shall
be entitled to receive unaudited quarterly and audited annual financial
statements.


    IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by its
duly authorized officer.


Signature: /s/ Reinaldo F. Gomez                  Dated:  12/22/92
           COMPANY: TERRAPIN TECHNOLOGIES, INC.
<PAGE>

Accepted:  WARRANTHOLDER


Signature: /s/ Glen McLaughlin
Print Name: Glen McLaughlin


<PAGE>

the undersigned further represents that it does not have any contract,
undertaking, agreement or arrangement with any person to sell, transfer, or
grant participations to such person or to any third person, with respect to any
Securities issuable upon exercise of the Warrant.

    (b)  The undersigned understands that the Securities issuable upon exercise
of the Warrant at the time of issuance may not be registered under the
Securities Act of 1933, as amended (the "Act"), and applicable state securities
laws, on the ground that the issuance of such securities is exempt pursuant to
Section 4(2) of the Act and state law exemptions relating to offers and sales
not by means of a public offering, and that the Company's reliance on such
exemptions is predicated on the undersigned's representations set forth herein.
The undersigned is an "Accredited Investor" as such term is defined in Rule 501
of the Securities and Exchange Commission.

    (c)  The undersigned agrees that in no event will it make a disposition of
any Securities acquired upon the exercise of the Warrant unless and until (i) it
shall have notified the Company of the proposed disposition and shall have
furnished the Company with a statement of the circumstances surrounding the
proposed disposition, and (ii) it shall have furnished the Company with an
opinion of counsel satisfactory to the Company and the Company's counsel to the
effect that (a) appropriate action necessary for compliance with the Act and any
applicable state securities laws has been taken or an exemption from the
registration requirements of the Act and such laws is available, and (B) that
the proposed transfer will not violate any of said laws.

    (d) The undersigned represents that it is able to fend for itself in the
transactions contemplated by this Statement, has such knowledge and experience
in financial and business matters as to be capable of evaluating the merits and
risks of its investments, and has the ability to bear the economic risks
(including the risk of a total loss) of its investment. The undersigned
represents that it has had the opportunity to ask questions of the Company
concerning the Company's business and assets and to obtain any additional
information which it considered necessary to verify the accuracy of or to
amplify the Company's disclosures, and has had all questions which have been
asked by it satisfactorily answered by the Company.

   (e) The undersigned acknowledges that the Securities issuable upon exercise
of the Warrant must be held indefinitely unless subsequently registered under
the Act or an exemption from such registration is available. The undersigned is
aware of the provisions of Rule 144 promulgated under the Act which permit
limited resale of shares purchased in a private placement subject to the
satisfaction of certain conditions, including, among other things, the existence
of a public market for the shares, the availability of certain current public
information about the Company, the resale occurring not less than two years
after a party has purchased and paid for the security to be sold, the sale being
through a "broker's transaction" or in transactions directly with a "market
maker" (as provided by Rule 144(f)) and the number of shares being sold during
any three-month period not exceeding specified limitations. The undersigned is
aware that the conditions for resale set forth in Rule 144 have not been
satisfied.


Dated: December 31, 1992



/s/ Glen McLaughlin
(signature)



GLEN McLAUGHLIN
(Typed or Printed Name)



(Title)