Three possible solutions for your problem:

1) Try downloading and installing the latest beta, maybe it'll fix it:
http://www.limewire.com/english/content/beta.shtml

2) Disable the option to connect LimeWire automatically when it is started:
Options->Connections
Then shut down LimeWire (completely, - kill it also from your system tray).
Then restart LimeWire and try to connect manually by going to File->Connect

3) search and delete the ".limewire" folder.

Please tell me, if any of it worked ;-)