I can't seem to get my head wrapped around the purpose of a MIB. I have a collection of ~20 MIB files that were supplied to me by the vendor, but what do I do with them?

I also have a few OID's that were supplied by the vendor that don't seem to be valid. When I issue an "snmpget -v1 -c public 192.168.0.123 .1.4.6.3.2.6.2" (assume that's a valid OID), I get an error indicating the variable is unknown. Does this sound like a hardware configuration problem? Do I need to "load" (for lack of better words) the MIB into the device?

Unfortunately, the vendor has been completely unresponsive with returning emails to my questions, so any help would be greatly appreciated.