In one of the deadliest acts of cinematic terrorism in recent years, the Palestinian Liberation Organization claimed responsibility Monday for the bombing of the Touchstone Pictures comedy Krippendorfs Tribe. 'To protest the continued Jewish occupation of our homeland, we have engineered the bombing of this film, creating singularly unappealing promotional ads and posters; giving it a formulaic script filled with tired, unfunny gags; and devoting more than 45 minutes of screen time to a naked, body-painted Richard Dreyfuss,' a PLO statement said of the bombing, which claimed the jobs of three Touchstone executives. 'Return Palestine to its rightful owners, or we shall mastermind a three-hour Steve Guttenberg/Shelley Long romantic comedy such that the world has never seen.' 