There was a time when David Zucker knew - really knew - how to direct comedy. After all, he directed or co-directed "Airplane," "Top Secret," "Ruthless People," and the first two "Naked Gun" films. He could take actors who'd never done physical comedy in their lives - Leslie Nielsen, Val Kilmer, Danny DeVito, even O.J. Simpson - and show them how to play it so straight and so well that his films became comedy icons for the 1980s.

Most of us underrate physical comedy. It looks as easy as the proverbial falling off a log, which of course is actually quite frightening to the faller, but it is as difficult in its way as ballet. Every movement must be choreographed and performed precisely, while looking to the audience like the most natural act in the world. Actors must do, not think; to be self-conscious is to undercut the moment and destroy the humor. Most actors are not natural comics, and it is the director's job to make them play as though they are.

Which brings us to "My Boss's Daughter," Zucker's current film. "My Boss's Daughter" is nothing more than an hour and a half of traditional slapstick: physical stunts, takes and double takes, and unexpected confrontations. Laurel and Hardy made a great joint career out of just those elements. Here Ashton Kutcher is young Tom Stansfield, researcher at the mega-company owned by control freak Jack Taylor (Terence Stamp). Tom has a crush on the boss's daughter Lisa (Tara Reid), but is too shy to let her know. Jack asks Tom to house-sit for the night, Tom thinks he'll be partying with Lisa, but quickly the house fills with unexpected visitors, everything goes wrong, and then is righted again at the end. Period..

Okay. That's the classic setup for a comedy that doesn't depend on verbal wit. It has served filmmakers well enough for a hundred years, and no doubt will continue to serve them for the next hundred. But "My Boss's Daughter" is a terrible movie, and there are two reasons why. Reason number one is Ashton Kutcher. If ever an actor was self-conscious, it is Kutcher. He cannot do anything, say anything, 'act' anything without letting us know that he is aware of what he's doing. This is death in comedy. So Kutcher sputters, stammers and twitches his way through the film like an out-of-control marionette.

Reason number two is Zucker himself. In physical comedy the directorial secret is calmness; the director must keep his or her cool. As hard as comic acting is, directing comedy well is harder. Jokes take time to set up and time to play out. The camera can't be as frantic, as consumed by the moment as the players. It needs to sit and observe what happens before it. The action is what's important, and the camera must not obtrude onto it. And camera placement must be carefully chosen as well. What is the proper distance from which the audience should view it? Should the camera be above, below, at eye level? Where will it be funniest? Zucker used to know, probably intuitively, just how to direct comedy, where to put the camera, and where to stage the action.

Here, though, he seems to have abandoned his talent. With a script that gives him a couple of dozen perfectly serviceable setups for good comedy he lets it all get out of hand, lose focus and destroy the wit. "My Boss's Daughter" was never going to be a classic of the genre, but between Zucker and Kutcher they've ensured that it will fail.