Can you download other files (eg music)? If other files download, chances are that you're seeing fake movie files. These will sit connecting for ages & then get stuck needing more sources forever. Is that what's happening? In that case, always check a movie before download with Bitzi. If the file's been rated, you'll get some idea of content & quality. If a file has lots of sources, but no Bitzi rating...chances are it's a fake.

Check out these threads for more info & tips (including Bitzi info).
Fake files showing up in search results
How to find music (tips for video, too)