WB Makes Buffy's Pre-Move Days Rough

May 3 -- Buffy the Vampire Slayer's last days on the WB aren't looking like halcyon ones.

The WB has scrapped plans to run a congratulatory ad for Buffy's 100th episode in The Hollywood Reporter next week. According to Variety, the show's defection to rival net UPN and creator Joss Whedon's harsh comments about the WB have caused the ad to be pulled. UPN has apparently bought its own Buffy ad in order to celebrate the mile marker.

In the May 4 issue of Entertainment Weekly, Whedon said his move to UPN is a welcome change: "There's a much greater comfort zone [at UPN] and a feeling of being appreciated, that this show is worth something, which was lacking at the highest level at the WB."

Promotional photos of the fresh-scrubbed Buffy cast have been pulled from the show's official WB Web site, making it nearly impossible for UPN (or members of the media) to get easy access to images, which WB execs fear could be used by the competition to promote the show. "We're only exercising our contractual right to exclusively promote the show," a WB spokesman told Variety.

An ad that aired immediately following Tuesday's Buffy episode trumpeted the fact that there are only three episodes left before "the WB series finale" of Buffy. According to Variety, that's technically true, but it does mislead viewers into thinking that the show is ending altogether.

The WB was reportedly unwilling to pay more than $1.8 million per episode to the show's producer, 20th Century Fox, while UPN stepped up with a reported offer of $2.35 million per episode.

The show will leave the WB at the end of summer.

Reuters contributed to this story.