You might be trying to download fake files. These will sit connecting for ages & then get stuck needing sources forever. If you're trying to download movies which are still in the cinema & haven't been released on DVD yet, there's a good chance that most files showing up in search results will be fake.

Always check a movie with Bitzi before download. If other users have rated the file, you'll get an idea of it's quality & content (can help you avoid misnamed files). If a file has heaps of sources but no Bitzi rating, chances are it's a fake. There's a link to Bitzi info in this thread.
Fake files showing up in search results