I'm running out of ideas...
You could try uninstalling Limewire using the uninstaller which is found in start > all programs > limewire...then re-install it using the offline installer...To find the offline installer, use the link below > cancel the installer window when it pop's up and then select the offline installer link...
Lime Wire » Download LimeWire If that doesn't help could you goggle your modem and see what info you come up with regarding port forwarding...I couldn't find anything...