B-Witched

It's never too late to switch the ending.

A group of young actors are forced to abandon their school stage and move into an abandoned playhouse in Hollywood, when their play about the Salem witch trials is found to be distasteful. They discover an old book of "spells", which is used during a rehearsal. The incantation releases a witch, who goes on a killing spree, taking the hearts of the actors to open up the door to hell for her master, Satan.