Michael Paloma is seeking $4 million plus compensatory and punitive damages against then-named Beverly Hills Film Studio for the movie, which was filmed in California last year, Zap2it.com reported.
The suit claims Paloma's company, Red Rock Entertainment, had a 51 percent interest and director BJ Davis a 49 percent interest.
The suit says Davis subsequently resigned as the studio's president and was replaced by Kimberly Kates, who agreed to finish the movie under the deal Paloma made with the Beverly Hills studio, but then backed out.
Beverly Hills Film Studio has since changed its name to Bigscreen Entertainment.
"Forget About It" revolves around three retired men spending their twilight years in Arizona when they're pulled into a scheme involving the mob and distracted by Welch. The film also stars Robert Loggia, Charles Durning, Phyllis Diller and Richard Grieco.
(Correcting studio, actor's names)