I'm still having my SNMP problem (and after yesterday, I'm not really any closer than I was on Monday. Today I'm trying every other SNMP module I can find, and any other ideas I have. If it doesn't work by the end of the day, I'm going to forget using the module and just parse the output of the snmpwalk command. Sigh.
Presently I think I'm installing an alternative module to Net::SNMP which will actually talk directly to the same library that snmpwalk uses. I suppose Net::SNMP is a pure Perl implementation of the protocol.
I did discover that when I try to do what snmpwalk does, which I think consists of repeated calls to get_next_request, it simply skips this Counter64 value (I should get the MIB that points at it returned at some point, but I never do; it simply returns the next non-Counter64 value), while when I pass in that MIB directly to get_request, it gives me this error: "Received noSuchName(2) error-status at error-index 1." Whatever that is.