Please help:

Trying to run Limewire behind Winroute Pro and can't get any where at all.

I have tried enabling packet filtering on TCP and UDP for port 6346

I have also enabled Port mapping 6346 to my machines IP and still no joy.

Any ideas please?

AFAIK enabling packet filtering means that packets with that port were blocked. Port mapping means that packets directed to one port are redirected to another port (on the same machine). Sending packets directed to a port on the masquerading host to another host, maybe the same port or another, usually is called port forwarding.
If you block the packets there is nothing left to redirect or forward.