A person who worked for me is now claiming partial ownership of the
business despite not holding any stock, not contributing any initial
capital nor holding an officer's position in the corporation.   This
person did have access to the daily cash and managed to take over
$150,000 from the business.   
    Another business owner told me that dividends from a subchapter S
corporation HAVE to be distributed equally.  What are the laws
regarding dividends when there are two "partners" in a subchapter S
corporation ?  There is not a reference to dividends in the
corporation papers for my business.

Hello and thank you for your question.

Yes, dividends from a subchapter S corporation have to be distributed
in proportion to stock ownership.  Which means equally between 50-50
shareholders.

The reason is the one-class-of-stock requirement of Internal Revenue
Code Section 1361(b)(1)(D).
Section 1361(b)
    (b) Small business corporation

      (1) In general

        For purposes of this subchapter, the term ''small business

      corporation'' means a domestic corporation which is not an

      ineligible corporation and which does not -

          (A) have more than 75 shareholders,

          (B) have as a shareholder a person (other than an estate, a

        trust described in subsection (c)(2), or an organization

        described in subsection (c)(6)) who is not an individual,

          (C) have a nonresident alien as a shareholder, and

          (D) have more than 1 class of stock.
http://uscode.house.gov/usc.htm
[you'll need to put 1361 in the search box]

"A corporation is considered to have one class of stock if all of its
outstanding shares bestow equal rights to distributions [dividends]
and liquidation yield."
CPA Journal Online
http://www.nysscpa.org/cpajournal/old/14345301.htm

So in the case of your company, chances are you only have common stock
of a single class, and all of it has been issued to you.  As sole
stockholder, you get any and all dividends.  Your would-be partner
cannot share in those dividends unless your partner is a stockholder.

Search terms used:
internal revenue code
1361 regulations dividends

Thanks again for bringing us your question.

Sincerely,
Google Answers Researcher
Richard-ga