In limewire

Go to Tools -> Options -> Advanced -> Firewall Config

Tell us what settings you use there

Also check your user manual for info on the modem. Like if there might be a firewall etc. in it.

I searched the net for similar cases and only found one (Which btw had no fix). Very few posts deal with any issues with that modem.

Also have you installed any software lately that can cause a firewall like block?