I just compiled grass 6.2.1 on 2 computers, one runs FC5 and the other FC6. nviz works fine on the FC5 machine, but it locks-up on the FC6 system. Specifically, entering nviz -q causes the nviz window and the "please wait ..." windows to open. The nviz window remains empty and "please wait ..." never goes away on the FC6 system. Any suggestions?