Are you using Windows?? If so...

Try this first: Delete LW's preferences folder when LW's properly closed. See point 3 here & also point 2 if you've used 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 you're not sure of your settings, go through LW's tools > options & write them all down, so that you can reset things later.

If files are always needing more sources, you might be seeing fake files. Make sure to check the file with Bitzi before download. If the file has heaps of sources but no Bitzi rating, chances are it's a fake. The thread below has more info, including how to use Bitzi
Fake files showing up in search results

Lots of .mov files are spam/porn. You might want to consider adding .mov to your keyword filter (to filter out these files). Tools > options > filters > keyword will get you to the filter page.
mov files