I don't know which OS you're using, but if you're using OSX or Win XP & use the latest Java & LW, I'd suggest it shouldn't happen again. This issue was more common with the older OS's, earlier versions of Java & LW.
Keep in mind that items listed in red in the incmplete folder can be b/c they've lost their link/relationship with the original source. Searching for the file & selecting to dwnld until you find the right one that dwnlds & continues on from where the incomplete one was is 'THE' most effective way of doing it. Force resuming the red files inevitably (but not always) ends up with them beginning from 0%! See this:
http://www.gnutellaforums.com/showth...threadid=26449