The loading order is the most important and common problem when you are loading MIBs. Many MIBs use definitions that are defined in other MIBs. These definitions are listed in the IMPORTS clause near the top of the MIB.
For example, if MIB mumble imports a definition from MIB bumble, some MIB compilers require you to load MIB bumble prior to loading MIB mumble. If you get the load order wrong, the compiler will claim that the imported MIBs are undefined.
This is a list of MIBs from which many other MIBs import, and the order in which you should load them. This will take care of most of load order issues (most of the other MIBs can be loaded in any order):
Note: If you are loading the v1 versions of these MIBs, the MIB filename will actually look like IF-MIB-V1SMI.my (“-V1SMI” is added to the name of MIBs that have been converted from v2 to v1). The exception to this is the RFC1213-MIB.my MIB, which only exists as a v1 version (that is, there is no RFC1213-MIB-V1SMI.my).
If you attempt to load another MIB, and if the compiler complains about undefined items, then identify from which MIBs this MIB is importing and verify that you have loaded all the other MIBs first.