You could be seeing fake files. These will sit connecting for ages & then get stuck needing more sources forever. They won't ever download. Always check a movie before download with Bitzi. If other users have rated the file, you'll get an idea of it's content & quality. Files with heaps of sources (in the # column) but no Bitzi rating are usually fake.

Check these threads for more info & tips.
Fake files showing up in search results
How to find music (tips for video as well)