LOS ANGELES —  A judge has ordered a film production company co-founded by Madonna and another firm to enter into mediation to try to settle a legal dispute involving competing plans to make a movie on prisoner abuse.

Attorneys for Madonna's Maverick Films and Beverly Hills-based Inferno Distribution were ordered by a Los Angeles Superior Court judge Monday to report back May 22 to provide an update on mediation efforts.

Judge Mary Ann Murphy also set a Jan. 16, 2008, trial date in case the dispute wasn't settled.

Maverick Films sued last October, claiming Inferno Distribution unfairly represented itself to gain access to confidential information about a movie Maverick was making called "The Stanford Prison Experiment."

Inferno Distribution countersued last December, alleging slander, unfair competition and interference with contractual relations. The countersuit said the company was trying to make an English-language version of a German movie that examined the psychological effects of prison.

Maverick Films was founded by Madonna and Maverick Records executive Guy Oseary in 2001. The company acquired rights to the story in 2002 from Stanford University psychologist Philip G. Zimbardo, who conducted an experiment on obedience in 1971.