Several things you can try. But 1st you should configure all your firewalls to allow both LW & Java full access & yes your router has an internal NAT firewall which will require a port to be forwarded.
1. Common firewall instructions:
http://www.limewire.com/english/content/firewalls.shtml
2. Set up a static IP instruction at the following link BEFOE opening a port for LW to have full access.
Port Forwarding instructions for the Dlink DI-604
3. Force IP within LW:
Force IP instructions & sample image
4. Update your Java:
http://www.limewire.com/english/cont...radejava.shtml
5. Repair LimeWire using the Add/Remove Programs utility. Go to Control Panel then Add/Remove Programs & click on Limewire on the Change/Remove button & it comes up with options and one of them is Repair. Try this.
6. Right-clicking the Limewire icon and going to properties and changed compatability setting to Windows 2000.
Try these things 1st & see how they go.