Did you update to SP2 (Service Pack 2)? If do that could be your problem! Either do a forum Search for SP2 or look at: http://www.gnutellaforums.com/showth...threadid=28437
which includes 2/3 of suggestions of how to combat the SP2 issue.

Oh if you haven't already update your java: either Java 1.4.x or else Java 1.5 (take the JRE)

At the very worst you may need to delete your incomplete files. But try all options 1st.