ciscoMgmt is from the CISCO-SMI MIB. ciscoBusMIB is from CISCO-BUS-MIB. Noet that evey MIB has some pre-requisite MIBs defined under the IMPORTS section of that particular MIB that must be loaded first, other wise you'll see errors. Meaning that there's a specific MIB Loading order that must be followed. In your case the error indicates that CISCO-SMI MIB must be loaded first. This is true for all MIB loading/compilation.
Have a look at http://www.cisco.com/warp/public/477/SNMP/mibs_9226.shtml that talks about this in more detail. Especially look at the sections 'What Are the Minimum or Pre-requisite MIBs that I Need?' and 'MIB Compilers: What Are They? Do You Care? What Issues Might You Encounter and What Are the Workarounds? and '1. Load ordering: ' in the above doc which should clear this up for you.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...