If you were in the process of downloading these files and lost power or rebooted there is a good chance these files are corrupted.

See these threads:
http://www.gnutellaforums.com/showth...?threadid=3519
http://sourceforge.net/forum/forum.p...forum_id=14293

If you still think the problem is with Gnucleus you might try Oasis, it will resume from partial files created by Gnucleus.