Did you by any chance have portforwarded your Limewire port in the previous version. If so check if your port has changed when you installed the new version.

Tools>Options>Advanced>Firewall config

Also if your exeptions were added for the older version. Your firewall may not recognize the new version as the same program. Try deleting the exeptions for Limewire and adding new ones

If you haven't portforwarded Limewire then make sure UPnP is enabled