Trailers for “The Hangover: Part 2” are being pulled from theaters for violating an MPAA rule stating that films can only trailer before similarly rated movies.

The R-rated Warner Bros. laffer was being promoted at screenings for the PG-13-rated “Source Code,” afoul of the Motion Picture Assn. of America’s guildelines. “Source Code” was the only film in the marketplace that featured the trailer.

“In our haste to meet the placement schedule for this trailer, we failed to properly vet the final version with the MPAA,” the studio said in a statement. “We acted immediately to correct the mistake and removed the trailer from screens.”

“Hangover 2,” which opens nationwide on May 26, now will trailer before R-rated “Scream 4” when it bows on April 15. That trailer has been approved by the MPAA, according to Warners, for both R-rated placement and online use.