Please give us your system details as listed here
http://www.gnutellaforums.com/connection-problems/62652-system-details-help-us-help-you-provide-these-details-when-you-post.html Ram OS and Disk space are essential.
Updating your Java might be the problem and you should take a look at this
http://www.gnutellaforums.com/windows/36420-fixes-limewire-when-lw-isn-t-operating-should.html but if you have tried other Java based applications, this is not so likely to be the problem