Somewhere in a conference room at Dreamworks, it must have gone like this:

"Here's the pitch: Screwball comedy meets The Sopranos. It can't miss. And listen to this: We have the two hottest stars in the business for the leads, PLUS that Gandolfini guy from HBO, and he plays an actual HIT MAN, and then at the end we give them one last zinger: Gene Hackman to wind up the plot. Is that great or what?"

Not only is "The Mexican" not great, it's not even good. Brad Pitt and Julia Roberts flail around in a script that might as well have been written for Penny Marshall and The Fonz. Pitt is Jerry, a hapless underling for a Los Angeles crime boss who wants a legendary handmade Mexican pistol and sends him south to bring it back. Roberts is his about-to-be-ex-girlfriend Samantha, who wants him to leave the mob life and go with her to Las Vegas where she will try to become a croupier.

So he goes south and she goes northeast, and never the twain shall meet, at least in this film, until almost two hours later, which tells us that the end is finally near. While he bumbles through rural Mexico, she is kidnapped and held hostage by killer Gandolfini - a huge amount is made of the fact that his character is a closeted gay, who is comforted and opened up by Roberts in the course of the kidnapping.

Many things go wrong in the film, but an interesting one is the use of Pitt. He is gorgeous to look at, and is a very fine character actor with a wide range - "Thelma and Louise," "Twelve Monkeys," "True Romance," "Fight Club," and the recent "Snatch" come to mind - but he is not a sexy screen icon, as a screwball film lead must be. Instead, he plays against even the hint of sex appeal here, acting like an overgrown teenager caught copying a test.

This is not his fault. The script, by J.H. Wyman, is a confused muddle that starts with the breakup of Jerry and Samantha and then alternates following each of them on their supposed adventures, a thousand miles apart. There is no hint of anything resembling a past or present relationship between them, no reference to a past together, no hint of a future. The closest Samantha comes to anyone is when she encourages Gandolfini, as Leroy the hit man, to come out of the closet. And it is obvious that his supposed orientation was thrown into the film for no other reason than the titillation of seeing Tony Soprano's actor pretend to be gay.

Roberts does her best with a part so generic that any of a hundred actresses could have played it just as well. It consists primarily of getting mad. She gets mad at Jerry, she gets mad at Leroy, she gets mad at Jerry again, she still is mad at Jerry, she - well, you understand that she's really angry.

In a good comedy of this genre, the filmmakers build up tension, and then relieve it for us with a payoff: either a physical or verbal explosion. Enough of these, and you have a successful feature film. Here, director Gore Verbinski and writer Wyman leave the payoffs someplace off screen, so that there is never a sense of logic, or pleasure, or wit, or catharsis, behind what the audience sees. Moreover, Wyman seems unsure of just how much of a comedy this should be. There are unmotivated killings, mismatched sequences, and what might in better hands have been a series of "Run Lola Run" moments, when three stories are told and enacted about the legend surrounding the making of the famous pistol. Each of them falls flat.