I think it was that the MIBs that were in Solarwinds were incorrect for the current Geist version. I did a MIBWalk on various Geist MIBs when I had one of the Geist's web front end up to compare the numbers I got back.
Here are some of the MIBs I'm using to pull back temps. Hopefully this will help you get started.
AirTemp
MIB = 1.3.6.1.4.1.21239.2.5.1.6.1
Format = Enumeration
MIB Value Type = Raw Value
SNMP Get Type = GET
TempSensor
MIB = 1.3.6.1.4.1.21239.2.2.1.6.1
Format = Enumeration
MIB Value Type = Raw Value
SNMP Get Type = GET