What would it take to make one wax nostalgic for a campy old seventies kids’ TV show like “Last of the Lost”? You know, the one where “Marshall, Will and Holly, on a routine expedition, met the greatest earthquake ever known” and were catapulted into a different dimension inhabited by dinosaurs, pakus (i.e., monkey-creatures) and, of course, those creepy, slow-moving Sleestak? The answer, my friends, is this wretched updating that recasts the program as a vehicle for Will Ferrell. It has far better effects, of course—but any twelve-year old with a computer could improve on the ones Sid and Marty Krofft managed thirty-five years ago. (Even Gumby was more convincing than their T-Rex.) But it’s so awful that watching all forty-three episodes of the original without a break would be less painful than sitting through it.

In this version, Marshall, Will and Holly aren’t a father and his two kids, but rather three adults with juvenile brains. Rick Marshall (Ferrell) is a loony scientist who’s drummed out of the academic community for his obsession with temporal and dimensional warps that can be jumped by amplifying waves radiated by a type of rock. (Don’t bother trying to make sense of any of the script’s pseudo-explanatory gobbledegook, which the old show merely ignored.) Spurred on by Holly Cantrell (Anna Friel), a pretty doctoral student and Marshall devotee from England, the goofball builds a machine that takes them, along with redneck Will Stanton (Danny McBride), the owner of an amusement-park cave where they test the device, to the land where the dinos, pakus and Sleestak roam and where bits and pieces of eras past have been deposited randomly over the years.

The trio have to recover Marshall’s device, which has been mislaid during their transport, to open a portal home. But in the process they befriend Chaka (Jorma Taccone), a pint-sized paku who claims to be a prince (and for some unexplained reason is about to be sacrificed by two of his kind when they happen on him), and encounter not only the lumbering Sleestak but an advanced version of them, Enik (John Boylan), who enlists their aid in defeating The Zarn (voiced by Leonard Nimoy), who wants to destroy not just the land of the lost but earth, too. Or so Enik says.

The old TV show wasn’t a comedy, but it was unintentionally funny; this movie is billed as a comedy, but it has virtually no laughs, apart from a couple associated with the insertion of well-known songs (a device that’s become a real crutch for lazy screenwriters). And the Krofft version had the tone of an innocent adventure that the picture utterly lacks. It loses any feeling of family solidarity with its first mistake—replacing the kids with adults—and then compounds the error by employing “Jurassic Park” effects to inject truly threatening, sometimes (as in the case of an ice-cream vendor) ugly action to replace the happily goofy dino-stuff of the original. It makes matters worse by indulging in an orgy of gross-out, suggestive humor—even Chaka has been transformed into a lip-smacking, lascivious creature, and drug jokes are dropped in pointlessly throughout. (If you can believe it, a Polish joke even makes an appearance.) And the whole mess is thrown together so carelessly that the most rudimentary narrative logical required even of pictures aimed at toddlers is missing. It plays like a series of terrible sketches rather than a real movie.

Then there’s Ferrell, doing his usual shtick as a dumb, obnoxious fellow we’re supposed to find lovable, for reasons that surpass understanding. He’s awful, mugging relentlessly while spouting gruesomely mirthless lines—and yes, he finds the opportunity to strip down in his sadly customary fashion, so that we can have the pleasure of wincing at the sight of his puffy white flesh again. (The closeups also once more reveal the horrible state of his teeth; get thee to a dentist!)

Friel has some life as the spunky Holly, but McBride is no better than Ferrell. He sure does lose that redneck accent right quick—just too hard to maintain, one supposes—and then bulldozes his way through dialogue that he must have realized would drop dead on the floor as soon as he recited it. The only other people of consequence in the cast are Taccone and Boylon—the former creepy, the latter happily unrecognizable in his intentionally chintzy Sleestak outfit—and Matt Lauer, who appears as himself in atrocious bookending “Today” show segments that conclusively demonstrate he shouldn’t give up his day job. (If this is an example of the synergy between Universal and NBC, they should be quickly broken up.) Nimoy’s appearance amounts to the briefest of voiceover cameos, but it’s enough to put a bad taste on his “Star Trek” triumph.

But then it’s hard to imagine anyone could have overcome the sheer ineptitude of Brad Silberling’s direction. Perhaps he was so obsessed with trying to integrate the effects with the live action that he forgot that the human performers need some attention, too. Or maybe Ferrell is just uncontrollable.

In any event, it’s impossible to overstate how bad “Land of the Lost” is—we’re in “Howard the Duck” and “Pluto Nash” territory here. Though you might find it hard to believe, it’s a more disastrous reworking of an old kiddie staple than either “Dudley Do-Right” or “The Adventures of Rocky and Bullwinkle.” Fans of the old show will hate it, and non-fans will hate it even more.