Roberto Benigni's Life Is Beautiful aside, milking the Holocaust for laughs is a dangerous game. Even the blackest, most therapeutic humor turns queasy in the shadow of such monstrous evil; it's like dancing on a mass grave. So Jakob the Liar 's got a hard road to hoe--its eponymous schlemiel plays out his semi-farcical adventures in the mean streets of the Warsaw Ghetto circa 1944. The skies are always leaden over Jakob's hometown, reflecting the comic climate … mehrthat pervades this mostly unfortunate adaptation of Jurek Becker's autobiographical book (first filmed in 1975). Jakob Heym (Robin Williams in overbearingly earnest mode) gets tangled in a string of self-perpetuating lies about a hidden radio, supposedly broadcasting news that the victorious Red Army is nearing. His desperate attempts to convince a clutch of insistently idiosyncratic friends (clichés to a man: Liev Schreiber, Bob Balaban, Michael Jeter, Alan Arkin) and obligatory Nazi bad guys that the radio doesn't exist are complicated by the fact that he's stashed a fugitive kid (a dead ringer--sorry!--for Anne Frank) in his attic--and by abundant evidence that lies are the best medicine for the ghetto's skyrocketing suicide rate. Copious unfunny misunderstandings and pratfalls eventuate in this Holocaust rendition of Fiddler on the Roof (you expect Williams to break into song: "If I were a funny man...."). Ultimately, Jakob the Liar loses its way for good in some very ugly violence and a rather nasty final twist: the film's ending might just be rubbing our noses in another feel-good lie. --Kathleen Murphy weniger