It's the same code, but different issues. Khen suggested I turn on debugging for the no response issue, which appears to be host specific. For that, I'll put a sniffer on the wire as you suggest, but I'm not good at reading those. I think my current problem with why Net::SNMP doesn't do what I want is the following:

SolarWinds will do a MIB walk, starting on the branch OID that I specified and I'm assuming that's how it 'discovers' the other device specific OIDs. What I'm trying to do with Net::SNMP is essentially the same thing, but I now understand that the get_request and get_bulk_request methods are for known OIDs rather than a MIB walk. So it may turn out that Net::SNMP can't do a MIB walk? At this point I don't understand enough of the module to know for sure. I'll keep working on it and hopefully people will post back with other useful pointers for me.

Regards,
Scott