Carolco: Three potential bidders may try to torpedo Twentieth Century Fox's $50-million tentative deal to buy most of the assets of troubled movie producer Carolco Pictures. Carolco bondholders have filed an objection to the Fox agreement in U.S. Bankruptcy Court in Los Angeles, arguing, among other things, that the companies need to specify more clearly how much Fox is paying for Carolco's various parts. Carolco filed to reorganize under Chapter 11 of the Bankruptcy Code, and its fate will ultimately be determined by a bankruptcy judge. The objection by bondholders is being supported by potential bidder PolyGram Filmed Entertainment. Sources also said that French television company Canal Plus is a serious potential bidder for Carolco, and possibly even studio giant Warner Bros. Carolco produced such big-budget films as "Terminator 2: Judgment Day," "Basic Instinct" and the new "Cutthroat Island."