Install IPX protocol with default values.
Then start regedit and go to:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NwlnkIpx\Pa rameters
Change DWORD value SocketUniqueness into 20 (hexadecimal)
Then go to HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NwlnkIpx\Pa rameters\Adapte rs\{your adapter}
Change DWORD value MaxPktSize into 10 (hexadecimal)

You have to do this on every computer you want to play hosted Carmageddon 2 games with.

We had the same problem. After spending a few hours on the problem I made a few guys here very happy. Hope it helps you

Eelko Neven