Try downloading some music files. Search for old songs (2 years plus) & try to download files with 10 sources or less, or even those with a single modem source. What happens?

If the files download, then I'd say you've just been really unlucky with the movies you're trying to get & are seeing fake files.

If the files don't download (do the connecting/need sources thing) then try this: Delete LW's preferences folder when LW's properly closed. See point 3 here & also point 2 if you've used much older versions of LW in the past (there could be a folder in either location).
Fixes for LimeWire
This will kill all of your settings within options, you'll have to go back through afterwards & reset things.

If that doesn't help, you could try the Beta version (has torrent support). The latest Beta's 4.13.4 & you can download it from the normal LW download page, or from your personal download link if you have Pro.