The American Pie filmmaker helmed the eagerly awaited 2007 movie, which starred Daniel Craig and Nicole Kidman.
The film, based on the hugely successful but controversial His Dark Materials novel series by Philip Pullman, was expected to be the first of a lucrative franchise, but the movie flopped at the box office and the sequels have never been made.
And Weitz blames its failure on studio boss' insistence on stripping key elements of the novel because they have been perceived as anti-Catholic Church. Religious groups even called for a boycott of the film ahead of its release.
Weitz says, "They felt they couldn't deal with having a film that was going to cause religious controversy. But it would've been a different story if I'd had final cut. It's the greatest professional regret that I have."