Hi all: I agree with previous poster imdb.com is good resource for movie bloopers. I think the website
www.tv.com which has listings of shows, also has a blunders/errors section, where you look them up by episode.
That being said, back in college the guys in the TV department were always talking about a huge continuity error in the original "Star Wars" movie. They couldn't believe I didn't know about it. They said was huge--really quite huge. Sadly George Lucas I think has long corrected it. I think it was a scene though were they were in the Millenial Falcon trying to escape, as I recall the guys describing it to me.