Template:FAQ:Coding 03
From Net-SNMP Wiki
This basically means that it hasn't loaded the MIB file containing
the definition of the MIB subtree you're trying to implement. This
might be because it hasn't been installed, the name is wrong, or
(most likely), because it isn't in the default list. See the
MIBS section for more details, or the next entry for suitable invocations
of mib2c.
