<PAGE>   1
                                                                     EXHIBIT 3.6



                            CERTIFICATE OF AMENDMENT
                                       OF
                            ARTICLES OF INCORPORATION
                                       OF
                        THE L.L. KNICKERBOCKER CO., INC.



           LOUIS L. KNICKERBOCKER and WILLIAM R. BLACK certify that:

        1. They are the duly elected and acting Chairman of the Board and
Secretary, respectively, of THE L.L. KNICKERBOCKER CO., INC., a California
corporation (the "Corporation").

        2. Article IV of the Articles of Incorporation of this Corporation is
amended to read as follows:

                "This corporation is authorized to issue two classes of stock,
        to be designated, respectively, "Common Stock" and "Preferred Stock."
        The total number of shares which the corporation is authorized to issue
        is One Hundred Ten Million (110,000,000) shares. One Hundred Million
        (100,000,000) shares shall be Common Stock and Ten Million (10,000,000)
        shares shall be Preferred Stock.

                The Preferred Stock may be issued from time to time in one or
        more series as the board of directors (the "Board of Directors") of this
        corporation may determine. The Board of Directors is authorized to
        determine and alter the rights, preferences, privileges and restrictions
        granted to or imposed upon any wholly unissued series of Preferred
        Stock, and to fix the number of shares of any series of Preferred Stock
        and the designation of any such series of Preferred Stock. The Board of
        Directors, within the limits and restrictions stated in any resolution
        or resolutions of the Board of Directors originally fixing the number of
        shares constituting any series, may increase or decrease (but not below
        the number of shares of such series then outstanding) the number of
        shares of any series subsequent to the issue of shares of that series.
        In case the number of shares of any series shall be so decreased, the
        shares constituting such decrease shall resume the status that they had
        prior to the adoption of the resolution originally fixing the number of
        shares of such series."

        3. The amendment herein set forth has been duly approved by the Board of
Directors of this Corporation.



<PAGE>   2




        4. The amendment herein set forth has been duly approved by the required
vote of the shareholders of this Corporation in accordance with Section 902 of
the California Corporation Code. The Corporation has only one class of shares
and the total number of outstanding shares entitled to vote with respect to the
amendment was 19,994,126. The number of shares voting in favor of the amendment
equaled or exceeded the vote required. The percentage vote required was more
than 50%.

        Each of the undersigned declares under penalty of perjury under the laws
of the State of California that the matters set forth in this Certificate are
true and correct of his own knowledge.

Dated: March 15, 1999

                                              /s/ Louis L. Knickerbocker
                                             -----------------------------------
                                             Louis L. Knickerbocker,
                                             Chairman of the Board


                                              /s/ William R. Black
                                             -----------------------------------
                                             William R. Black, Secretary