Its not my router. Like I said, everything worked fine with a fresh install of winXP. I have also taken the one machine off the router, placed it directly to the cable modem and I still have the same result.
The router I have has been flashed with the latest bios, has been properly configured and works great.
I have also recently done a reinstall of winXP on another machine (which is behind my router) and mirc is fully functional, but the other machine still is experiencing the same send/recieve problem.
It just really boggles my mind how this is occuring.