Universal Studios has backed out of backing the movie, whose budget the source pegged at nearly $100 million, because Mr. Rodriguez has insisted on casting his new fiancé, Rose McGowan, in the lead role, famously played by Jane Fonda in the 1968 original directed by Ms. Fonda’s then-husband, Roger Vadim.

The movie depicts a futuristic astronaut who travels the galaxy, seductively conquering everything in her path. More famous names floated for the part included Nicole Kidman, Halle Berry and Jessica Alba.

“It’s sort of embarrassing for everyone involved,” the source said. “No one thinks Rose can carry the movie, but Robert won’t listen.”

The film’s executive producer, Dino De Laurentiis, an Academy Award winner who produced Mr. Vadim’s Barbarella, is keeping mum on the matter, the source said. “He’s technically independent but has a strong connection to Universal. He wants to back Robert and his vision. But Robert’s vision is blurred by Rose.”

Universal’s initial excitement about the project had prompted reports that the movie would be fast-tracked for release in 2008. Indeed, the studio was so excited about the film that upon discovering Mr. Rodriguez’s nepotistic casting preference it came back with a second offer to fund Barbarella with an amount significantly below the original—in the double-digit millions, said the source. Apparently many of those involved have unsuccessfully tried to persuade Mr. Rodriguez to see his way beyond his curvaceous fiancée, best known for her role in the TV series Charmed.

But the director is sticking by his number-one chica, the source said, and with Ms. McGowan billed to fill Fonda’s thigh-high boots, the studio is afraid the box office simply wouldn’t stand up to the investment.

Mr. Rodriguez denied this, claiming the issue was simply one of budget. “Universal had initially signed on for $60 million,” he told the Transom, “but then when we were done with the script it wound up at closer to $82 million, and they had just financed a Will Ferrell movie that was a $130 million and they even cut that down to $100.”

He said Universal would still be happy to fund the picture for $60 million, but that he was shopping it around to other studios in the hopes of getting more money. Mr. Rodriguez is known for his ability to make movies cheaply, but believes it will be difficult with Barbarella since much of the film takes place in outer space, and “we don’t want the movie to look like the original,” he said.

The director alleges that the people at Universal were in fact thrilled with Ms. McGowan’s screen test, “blown over,” as he put it. “They said, ‘What are we looking at?’” Mr. Rodriguez said. “She looks fantastic in the role. … She was perfect for this part. She just has that daring look, a sort of classic sexiness that is also kind of futuristic.”

His bodacious Barbarella vision came to him while flipping through the trades one morning with his fiancée at his side. “I asked Rose, I said, ‘Would you be interested in doing this?’ And she said, ‘Oh, we’d rock that shit so hard.’” Mr. Rodriguez said. “And I said, ‘Well, that sounds like a lot of fun.’”

Reps for Mr. De Laurentiis and Universal had no comment.