The "disk problem" is a hairy one. Here are a few threads, there doesn't seem to be one nice, clean answer. Some people have had success after defragmenting the HDD.

http://www.gnutellaforums.com/showth...t=disk+problem
http://www.gnutellaforums.com/showth...t=disk+problem
http://www.gnutellaforums.com/showth...t=disk+problem
http://www.gnutellaforums.com/showth...t=disk+problem

And also this, which may be of absolutely no use at all but deals with files not verifying
http://www.gnutellaforums.com/showthread.php?t=55410