You might be trying to download fake files...they're all around now & are a PITA. They'll sit conecting for ages before showing 'need more sources' or 'awaiting sources but won't ever download!
Search again, vary your search terms, try the All Types search. Stay away from files with lots of sources, go for a file with 10 sources or less, or those with a modem source.
For movies, always check a file before download with Bitzi. A file with heaps of sources but no Bitzi rating is often a fake.
How to use Bitzi
For music, try the tips in this thread
How to find music
And for some general info about these fakes
Info about fake files