Q. What do these errors in the server debug log indicate?

"SNMP pkt not handled from, ID = 11771270"

A. This means that InterMapper didn't find the packet ID in our list of packets sent. The list is a circular buffer, so if a certain number of poll cycles go by without a reply for a given packet ID, the packet ID will age out and InterMapper won't recognize a packet which matches it if it comes in later.

It could also be that InterMapper received a packet that it didn't send. But the first explanation is more likely.