Sorry but you are wrong pitbull, you can run the OpenTCP stack with a watchdog on as I have done so without any problems. You just have to make sure that you kick the watchdog regularly.
To activate the watchdog apply the following code (btw this is in C)
COPCTL = 0x07;
void kick_WD (void) <------- this routine is in system.c
{
ARMCOP = 0x55;
ARMCOP = 0xAA;
}
All you have to do is make sure that you call kick_WD regularly to stop it from resetting the device.
Remember if something goes wrong in the code and you need to debug, you have to remove the COPCTL initialisation line.