The problem with "The D Train" isn’t the performances. Jack Black, James Marsden, Kathryn Hahn and Jeffrey Tambor are wonderful in their respective roles.

‘THE D TRAIN’ Rated: R Opens Friday

The issue is the story. It’s not just uneven, it’s often unfunny: tinged with homophobia and centered on a wholly unlikeable, self-absorbed man.

Dan Landsman (Black) is serious about his Pennsylvania high school’s 20th reunion and considers himself chairman of its organizing committee. He yearns desperately to be liked, but comes across as bossy and uncooperative, so when the group goes out for beers after committee meetings, they leave him behind.

Otherwise, Dan’s life looks pretty good. He seems happily married to his lovely, supportive wife (Hahn), has an admiring teenage son (talented newcomer Russell Posner) and works for a trusting, encouraging boss (Tambor).

Watching TV late one night, Dan spots his reunion solution: He sees a commercial starring a former classmate, the handsome and popular Oliver Lawless (Marsden), and decides if he can bring the now-actor back to their hometown, he’ll be in with the in-crowd, the hero of the reunion.

Dan lies to his wife and his boss about a fake business prospect in Los Angeles so he can talk to Lawless in person. By the time they meet, Dan is first-date nervous. He can’t see that Lawless is actually wasted and out of work. To Dan, he’s a superstar, a cool kid from high school.

Their meeting becomes a weekend of debauchery. They share an experience that makes Dan even more obsessed with the actor, even after he agrees to attend the reunion.

To say more would tread into the spoiler zone, but most of the attempted laughs thereafter are aimed at this obsession. The problem is that in a world where gender and sexuality exist on a spectrum, Dan’s response isn’t that far out.

This is where the story by screenwriters and first-time directors Jarrad Paul and Andrew Mogel begins to break down and the comedy turns sad. Dan may be a jerk, but even jerks can have their hearts broken.

A few laughs land, like Lawless’ advice for managing a threesome. And the soundtrack of 1980s hits is great, even if it doesn’t really fit Dan’s class of 1994.

"The D Train" rides entirely on its excellent cast. Marsden is flawless as Lawless, all sexy swagger and false nonchalance. Hahn heartbreakingly conveys unconditional love pushed to its limit. Tambor’s sincerity is transparent.

And Black is a profound actor. Even beyond his celebrated performance in 2011’s "Bernie," he’s achingly real and wrenchingly vulnerable here, giving heart to a character so unlikeable that even his eventual self-awareness wouldn’t be redemption enough.

The film ventures into brave territory for a buddy comedy with its twist on the trope of drunken one-night stands, but it ends up disappointingly sticking with stereotypes.