Debugging custom SNMP monitor

I am re-doing the device template for our Powerware UPS, as it does not work with our model (PW9315). I have all of the correct OIDs mapped out, and I can use the MIB browser to query each value and get the correct result. However, when I add these exact same OIDs to the device template, they do not work. For instance:

.1.3.6.1.4.1.534.1.4.1 (shows the UPS load)

This one returns the correct value from the MIB browser, but refuses to work from the added device when doing a "Test Monitor" -- it just says it isn't responding. What log file can I look at to debug this?

(running OpManager 8 on Win2003 R2 with MySQL DB)