Found a solution to this problem (probably not best or only one but...).
Set the local MUSR_MQADMIN's password to something so that we knew what it was (vs. the automatically generated behind the sce ...
After the Blaster et al Hotfixes (see Subject line) applied by our ServerOps, we (MQ support) had occurence of application being unable to interact w/ Q's via API on one box. This is on Windows Serve ...