I did some research and found the attached info in an older support log. Let me know if it helps you. If not, I'll do some more digging.
MIB_OID.txt 1.5 KB
FYI--as you can see, Brandon has provided the OIDs that are also in my doc in this thread. The doc does provide some additional info, which you may want to check out.
Thanks both, it was exactly what I was looking for.
Interface Errors and Discards:
OID = ifInDiscards
OID = ifInErrors
OID = ifOutDiscards
OID = ifOutErrors