If “Over Her Dead Body” serves only one useful purpose, it’s to prove that Paul Rudd is not automatically hilarious in any movie he’s in.

Rudd’s uncanny comic instincts are an essential part of half the decent comedies released in the last few years, including “The 40-Year-Old Virgin,” “Knocked Up,” and “The Ten.” By the way, check out an earlier, virtually unknown Rudd film, “The Chateau,” if you’re a fan.

But while Rudd scores a lead role in “Over Her Dead Body,” the film itself is too forced to really click. Sometimes plot defeats humor.

Rudd plays a man whose wife (Eva Longoria Parker) is accidentally killed by a falling ice sculpture on their wedding day. Despondent, he skeptically visits a psychic (Lake Bell) in hopes of contacting the departed.

Actually, it turns out the late bride is already on the scene. She’s a ghost. She disapproves of the romance brewing between her ex and the psychic, and takes earthly form to wreck the match.

This story is a variation on Noel Coward’s “Blithe Spirit” and dozens of other similar plots, but the ghost in this case is strangely mean-spirited and not terribly funny. Some of this might have to do with “Desperate Housewives” star Parker, who has plastic looks and a single-note delivery.

Most of the movie is about the Rudd and Bell characters, who actually work up some charm together. Lake Bell starred in a short-lived TV series, “Surface,” and has an unusual quality onscreen, both pretty and rowdy. Her offbeat timing goes well with Rudd.

Writer-director Jeff Lowell, who wrote the script to the occasionally funny “John Tucker Must Die,” creates room in which these actors can play. It isn’t a straight sitcom approach.

But the story itself is dreary, and other characters, such as Jason Biggs as Bell’s gay friend, are not memorable. The whole thing is just a little too laid-back and casual to really inspire much interest. But Rudd will be back.