Template:FAQ:Coding 06
From Net-SNMP Wiki
This is usually a sign of the same problem as above - giving mib2c the name of the file containing the MIB (or of the MIB itself), rather than an object within it.
Earlier versions of mib2c didn't detect this situation, and
rather than report an error, it merrily constructed a template
for a default starting point of the mib-2
node.
More recent versions issue the error mentioned above instead.