<PAGE>   1
                                                                    EXHIBIT 10.2

[IMPERIAL BANK LOGO]

                              PROMISSORY NOTE
<TABLE>

Principal      Loan Date       Maturity      Loan No.      Call      Collateral      Account     Officer    Initials
<S>            <C>             <C>           <C>           <C>       <C>             <C>         <C>        <C>
$2,000,000.00  06-12-1998      08-01-1999    716065529                                             900
</TABLE>

References in the shaded area are for Lender's use only and do not limit the
applicability of this document to any particular loan or item.
________________________________________________________________________________

Borrower: NATIONAL INSURANCE GROUP       Lender: Imperial Bank
          395 Oyster Point Blvd.                 East Bay Regional Office
          Suite 500                              1331 N. California Blvd.
          S. San Francisco, CA 94080             Suite 400
                                                 Walnut Creek, CA 94596-9504
________________________________________________________________________________

Principal Amount: $2,000,000.00 Initial Rate: 9.250%  Date of Note: May 12, 1998

          PROMISE TO PAY. NATIONAL INSURANCE GROUP ("Borrower") promises to
          pay to Imperial Bank ("Lender"), or order, in lawful money of the
          United States of America, the principal amount of Two Million & 00/100
          Dollars ($2,000,000.00) or so much as may be outstanding, together
          with interest on the unpaid outstanding principal balance of each
          advance. Interest shall be calculated from the date of each advance
          until payment of each advance.

          PAYMENT. Borrower will pay this loan in one payment of all
          outstanding principal plus all accrued unpaid interest on June 1,
          1999. In addition, Borrower will pay regular monthly payments of
          accrued unpaid interest beginning June 30, 1998, and all subsequent
          interest payments are due on the last day of each month after that.
          The annual interest rate for this Note is computed on a 365/360
          basis; that is, by applying the ratio of the annual interest rate
          over a year of 360 days, multiplied by the outstanding principal
          balance, multiplied by the actual number of days the principal
          balance is outstanding. Borrower will pay Lender at Lender's address
          shown above or at such other place as Lender may designate in
          writing. Unless otherwise agreed or required by applicable law,
          payments will be applied first to any unpaid collection costs and any
          late charges, then to any unpaid interest, and any remaining amount to
          principal.

          VARIABLE INTEREST RATE. The interest rate on this Note is subject to
          change from time to time based on changes in an index which is the
          Imperial Bank Prime Rate (the "Index"). The Prime Rate is the rate
          announced by Lender as its Prime Rate of interest from time to time.
          Lender will tell Borrower the current index rate upon Borrower's
          request. Borrower understands that Lender may make loans based on
          other rates as well. The interest rate change will not occur more
          often than each day. The Index currently is 8.500%. The interest rate
          to be applied to the unpaid principal balance of this Note will be at
          a rate of 0.750 percentage points over the Index, resulting in an
          initial rate of 9.250%. NOTICE: Under no circumstances will the
          interest rate on this Note be more than the maximum rate allowed by
          applicable law.

          PREPAYMENT; MINIMUM INTEREST CHARGE. In any event, even upon full
          prepayment of this Note, Borrower understands that Lender is entitled
          to a minimum interest charge of $250.00. Other than Borrower's
          obligation to pay any minimum interest charge, Borrower may pay
          without penalty all or a portion of the amount owed earlier than it
          is due. Early payments will not, unless agreed to by Lender in
          writing, relieve Borrower of Borrower's obligation to continue to
          make payments of accrued unpaid interest. Rather, they will reduce
          the principal balance due.


          LATE CHARGE. If a payment is 10 days or more late, Borrower will be
          charged 5.000% of the unpaid portion of the regularly scheduled
          payment.

          DEFAULT. If any event of default, as defined in the Credit Terms and
          Conditions Agreement dated April 2, 1997, other than a default in
          payment, is curable and if Borrower has not been given a notice of a
          breach of the same provision of this Note within the preceding
          twelve (12) months, it may be cured (an no event of default will
          have occurred) If Borrower, after receiving written notice from
          Lender demanding cure of such default: (a) cures the default within
          ten (10) days; or (b) if the cure requires more than ten (10) days,
          immediately initiates steps which Lender deems in Lender's sole
          discretion to be sufficient to   cure the default and thereafter
          continues and completes all reasonable and necessary steps sufficient
          to produce compliance as soon as reasonably practical.

          LENDER'S RIGHTS. Upon an event of default as defined in the Credit
          Terms and Conditions Agreement dated April 2, 1997, Lender may
          declare the entire unpaid principal balance on this Note and all
          accrued unpaid interest immediately due, without notice, and then
          Borrower will pay that amount. Upon Borrower's failure to pay all
          amounts declared due pursuant to this section, including failure to
          pay upon final maturity, Lender, at its option, may also, if
          permitted under applicable law, do one or both of the following: (a)
          increase the variable interest rate on this Note to 5.750 percentage
          points over the index, and (b) add any unpaid accrued interest to
          principal and such sum will bear interest therefrom until paid at the
          rate provided in this Note (including any increased rate). Lender
          may hire or pay someone else to help collect this Note if Borrower
          does not pay. Borrower also will pay Lender that amount. This
          includes, subject to any limits under applicable law, Lender's
          attorneys' fees and Lender's legal expenses whether or not there is a
          lawsuit, including attorneys' fees and legal expenses for bankruptcy
          proceedings (including efforts to modify or vacate any automatic
          stay or injunction), appeals, and any anticipated post-judgment
          collection services. Borrower also will pay any court costs, in
          addition to all other sums provided by law. This Note has been
          delivered to Lender and accepted by Lender in the State of
          California. If there is a lawsuit, Borrower agrees upon Lender's
          request to submit to the jurisdiction of the courts of Los Angeles
          County, the State of California. Lender and Borrower hereby waive the
          right to any jury trial in any action, proceeding, or counterclaim
          brought by either Lender or Borrower against the other. (Initial Here
          ____) This Note shall be governed by and  construed in accordance
          with the laws of the State of California.

          DISHONORED ITEM FEE. Borrower will pay a fee to Lender of $25.00 if
          Borrower makes a payment on Borrower's loan and the check or
          preauthorized charge with which Borrower pays is later dishonored.

          RIGHT OF SETOFF. Borrower grants to Lender a contractual possessory
          security interest in, and hereby assigns, conveys, delivers, pledges,
          and transfers to Lender all Borrower's right, title and interest in
          and to, Borrower's accounts with Lender (whether checking, savings,
          or some other account), including without limitation all accounts
          held jointly with someone else and all accounts Borrower may open
          in the future, excluding however all IRA and Keogh accounts, and all
          trust accounts for which the grant of a security interest would be
          prohibited by law. Borrower authorizes Lender, to the extent
          permitted by applicable law, to charge or setoff all sums owing on
          this Note against any and all such accounts.
       
          LINE OF CREDIT. This Note evidences a revolving line of credit.
          Advances under this Note may only be requested in writing by
          Borrower or by an authorized person. All communications,
          instructions, or directions by telephone or otherwise to Lender are to
          be directed to Lender's office shown above. The following party or
          parties are authorized to request advances under the line of credit
          until Lender receives from Borrower at Lender's address shown above
          written notice of revocation of their authority: Mark A. Speizer,
          Chairman/CEO; Bruce A. Cole, President; Robert P. Barbarowicz,
          Executive VP/Secretary; and Gregory S. Saunders, Executive VP/CFO.
          Borrower agrees to be liable for all sums either: (a) advanced in
          accordance with the instructions of an authorized person or (b)
          credited in any of Borrower's accounts with Lender. The unpaid
          principal balance owing on this Note at any time may be evidenced by
          endorsements on this Note or by Lender's internal records, including
          daily computer print-outs. Lender will have no obligation to advance
          funds under this note if: (a) Borrower or any guarantor is in default
          under the terms of this Note or any agreement that Borrower or any
          guarantor has with Lender, including any agreement made in connection
          with the signing of this Note; (b) Borrower or any guarantor ceases
          doing business or is insolvent; (c) any guarantor seeks, claims or
          otherwise attempts to limit, modify or revoke such guarantor's
          guarantee of this Note or any other loan with Lender; (d) Borrower has
          applied funds provided pursuant to this Note for purposes other than
          those authorized by Lender; or (e) Lender in good faith deems itself
          insecure under this Note or any other agreement between Lender and
          Borrower. 

          REFERENCE PROVISION. 1. Other than (i) non-judicial foreclosure and
          all matters in connection therewith regarding security interests in
          real or personal property; or (ii) the appointment of a receiver, or
          the exercise of other provisional remedies (any and all of which may
          be initiated pursuant to applicable law), each controversy, dispute
          or claim between the parties arising out of or relating to this
          document ("Agreement"), which controversy, dispute or claim is not
          settled in writing within thirty (30) days after the "Claim Date"
          (defined as the date on which a party subject to the Agreement gives
          written notice to all other parties that a controversy, dispute or
          claim exists), will be settled by a reference proceeding in
          California in accordance with the provisions of Section 638 et seq.
          of the California Code of Civil Procedure, or their successor
          section ("CCP"), which shall constitute the exclusive remedy for the
          settlement of any controversy, dispute or claim concerning this
          Agreement, including whether such controversy, dispute or
 
<PAGE>   2


05-12-1998                      PROMISSORY NOTE                           Page 2
                                  (Continued)
--------------------------------------------------------------------------------

claim is subject to the reference proceeding and except as set forth above, the
parties waive their rights to initiate any legal proceedings against each other
in any court or jurisdiction other than the Superior Court in the County where
the Real Property, if any, is located or Los Angeles County if none (the
"Court"). The referee shall be a retired Judge of the Court selected by mutual
agreement of the parties, and if they cannot so agree within forty-five (45)
days after the Claim Date, the referee shall be promptly selected by the
Presiding Judge of the Court (or his representative). The referee shall be
appointed to sit as a temporary judge, with all of the powers for a temporary
judge, as authorized by law, and upon selection should take and subscribe to the
oath of office as provided for in Rule 244 of the California Rules of Court (or
any subsequently enacted Rule). Each party shall have one peremptory challenge
pursuant to CCP 170.6. The referee shall (a) be requested to set the matter for
hearing within sixty (60) days after the Claim Date and (b) try any and all
issues of law or fact and report a statement of decision upon them, if possible,
within ninety (90) days of the Claim Date. Any decision rendered by the referee
will be final, binding and conclusive and judgment shall be entered pursuant to
CCP 644 in any court in the State of California having jurisdiction. Any party
may apply for a reference proceeding at any time after thirty (30) days
following notice to any other party of the nature of the controversy, dispute or
claim, by filing a petition for a hearing and/or trial. All discovery permitted
by this Agreement shall be completed no later than fifteen (15) days before the
first hearing date established by the referee. The referee may extend such
period in the event of a party's refusal to provide requested discovery for any
reason whatsoever, including, without limitation, legal objections raised to
such discovery or unavailability of a witness due to absence or illness. No
party shall be entitled to "priority" in conducting discovery. Depositions may
be taken by either party upon seven (7) days written notice, and request for
production or inspection of documents shall be responded to within ten (10) days
after service. All disputes relating to discovery which cannot be resolved by
the parties shall be submitted to the referee whose decision shall be final and
binding upon the parties. Pending appointment of the referee as provided herein,
the Superior Court is empowered to issue temporary and/or provisional remedies,
as appropriate.

2.   Except as expressly set forth in this Agreement, the referee shall
determine the manner in which the reference proceeding is conducted including
the time and place of all hearings, the order of presentation of evidence, and
all other questions that arise with respect to the course of the reference
proceeding. All proceedings and hearings conducted before the referee, except
for trial, shall be conducted without a court reporter, except that when any
party so requests, a court reporter will be used at any hearing conducted before
the referee. The party making such a request shall have the obligation to
arrange for and pay for the court reporter. The costs of the court reporter at
the trial shall be borne equally by the parties.

3.   The referee shall be required to determine all issues in accordance with
existing case law and the statutory laws of the State of California. The rules
of evidence applicable to proceedings at law in the State of California will be
applicable to the reference proceeding. The referee shall be empowered to enter
equitable as well as legal relief, to provide all temporary and/or provisional
remedies and to enter equitable orders that will be binding upon the parties.
The referee shall issue a single judgment at the close of the reference
proceeding which shall dispose of all of the claims of the parties that are the
subject of the reference. The parties hereto expressly reserve the right to
contest or appeal from the final judgment or any appealable order or appealable
judgment entered by the referee. The parties hereto expressly reserve the right
to finding of fact, conclusions of law, a written statement of decision, and the
right to move for a new trial or a different judgment, which new trial, if
granted, is also to be a reference proceeding under this provision.

4.   In the event that the enabling legislation which provides for appointment
of a referee is released (and no successor statute is enacted), any dispute
between the parties that would otherwise be determined by the reference
procedure herein described will be resolved and determined by arbitration. The
arbitration will be conducted by a retired judge of the Court, in accordance
with the California Arbitration Act, 1280 through 1294.2 of the CCP as amended
from time to time. The limitations with respect to discovery as set forth
hereinabove shall apply to any such arbitration proceeding.

CREDIT TERMS AND CONDITIONS AGREEMENT. This Note is subject to the provisions
of the Credit Terms and Conditions Agreement dated April 2, 1997 and all
amendments thereto and replacements therefor.

DEFAULT PROVISION. Any default under the obligations of New Arts Acquisition,
Inc. to Bank shall constitute a default hereunder. Defaults shall include those
defaults contained in the Credit Terms and Conditions executed by the
undersigned.

GENERAL PROVISIONS. Lender may delay or forgo enforcing any of its rights or
remedies under this Note without losing them. Borrower and any other person who
signs, guarantees or endorses this Note, to the extent allowed by law, waive any
applicable statute of limitations, presentment, demand for payment, protest and
notice of dishonor. Upon any change in the terms of this Note, and unless
otherwise expressly stated in writing, no party who signs this Note, whether as
maker, guarantor, accommodation maker or endorser, shall be released from
liability. All such parties agree that Lender may renew or extend (repeatedly
and for any length of time) this loan, or release any party or guarantor or
collateral; or impair, fail to realize upon or perfect Lender's security
interest in the collateral; and take any other action deemed necessary by Lender
without the consent of or notice to anyone. All such parties also agree that
Lender may modify this loan without the consent of or notice to anyone other
than the party with whom the modification is made.

PRIOR TO SIGNING THIS NOTE, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS OF
THIS NOTE, INCLUDING THE VARIABLE INTEREST RATE PROVISIONS. BORROWER AGREES TO
THE TERMS OF THE NOTE AND ACKNOWLEDGES RECEIPT OF A COMPLETED COPY OF THE NOTE.

BORROWER:

NATIONAL INSURANCE GROUP

X  /s/ ROBERT P. BARBAROWICZ
 ----------------------------
  Authorized Officer
  Robert P. Barbarowicz
  Executive Vice President  
  General Counsel and Secretary


================================================================================
Variable Rate, Line of Credit.             LASER PRO, Reg. U.S. Pat & T.M. Off.,
                                       Ver. 3.24b (c) 1996 CFI ProServices, Inc.
                     All rights reserved. (CA-D20 E.3.24 F3.24a 18NIG.LN C2-OVL)