Thank you for your reply.
I did watch the defgen tutorial, very informative!
First of all I must correct myself, there was a problem with both 3750-stacks.
I did a snmp-walk on both stacks and found that it took a loooong time to recieve the result from .18.104.22.168.22.214.171.124.1.2
One of the stacks had 1628 ARP entries, and the snmp-walk took 2 minuts and 20 seconds to complete.
On the other stack there was 3653 ARP entries, and I aborted the walk after 4 minutes.
I changed the time out for SNMP from 2 seconds to 180 seconds in nedi.conf and got good result from the first stack. I didn't do the test on the other stack but I am almost sure that if I had turned up the timeout even more I would eventually get result from the other stack.
On NeDi 1.0.7 the SNMP timeout was 2 seconds and NeDi was able to get the result anyway. Have there been any major changes in the way NeDi resolves ARP to IP after 1.0.7?
I have this problem with NeDiO8 and on NeDi 1.0.9 (nedi-240.tgz) but not on NeDi 1.0.7.