Go to Add/Remove programs and uninstall all Java versions. Then install latest version.
Check if some antivirus program or firewall is not blocking your LimeWire.
And, last from me, check this thread if previous is not working:
http://www.gnutellaforums.com/genera...tual_call.html

Or this sticky in this part of forum:
http://www.gnutellaforums.com/genera...wers-here.html

Thank you and good luck