qnet slow or non-functional

I have two “identical” computers running QNX 6.1 that have some problems
connecting using qnet.

If it do ls /net/pc1 from pc0 it frequently is very slow to respond -
sometimes the ls never returns.

We have the tcpip stack loaded and have no problems doing telnet or ftp
between the machines.

The machines are both 1.7 GHz P4 and are conencted to a 100 meg ethernet hub
using intel ethernet cards.