Don't try searching until Limewire has finished loading...it may take a few moments for your connections to finish handshaking.

Under the "View" tab:

You can show your connections.

If you are not getting any connections there is something blocking the port. If you have norton internet security, try disabling it, if you have norton internet worm protection, or the windows default firewall, add the specific port to your exceptions list.

If you are using a router, try port forwarding or advanced routing to open the specific port you are using.

Try those,

Good Luck!