The pages of a frameset show up in the wrong frame, or even open in a new browser window.
A common source of misbehavior in FrontPage-generated frames is setting an incorrect default target frame. Remember that the default target frame is a page property that specifies the frame in which the links display their destination pages. If this property refers to a nonexistent target frame, the destination page of the link will show up in a new browser window. If it refers to an existing but incorrect frame, the page will appear where you don't want it.