I have installed a few Watchdogs Supergoose II Environmental Monitors, and have configured SNMP on them. I then added it as a device and configured everything on the PRTG side.
I grabbed the Supergoose II MIB list. I have used your MIB Importer and created a OIDLib file which I added into my PRTG library (cool!). Then I dragged and dropped the device into the library and re-ran a auto-discover on it.
Unfortunately it came up with a bunch (about 20) sensors that say:
"This sensor has not recived any data since startup. Please check "SNMP Delay" channel of core/probe heath sensor. Consider distributing your SNMP sensors across several probes."
The server I have this device on is in fact an extra probe and barely anything on it. Also i can see the usual SNMP test sensors that were successfully added at the bottom of the SuperGoose II device list:
eth0 ICMP Messages In ICMP Messages Out (etc)
I even ran a prtg SNMP test and did in fact see responses.
I dont see any way to attach screen shots so i explained this the best i can.