Loading InRoads from within MS

Hello -

I like to load InRoads using a custom tool (keyin mdl load civustat.ma).  However, since updating to newer versions of both IR and MS, this tool no longer "works" and results in the following Message Center errors:

"MDL Loader:  Unable to load library (DLL or MDL shared library) CivUstAT"

"OS could not load C:\Program Files (x86)\Bentley\InRoads Group V8.11\bin\CivUstAT.dll, error 126."

The same occurs when trying to "load" from the Utilities->MDL dialog box (the CivUstAT.ma path is listed in both the MS_MDL and MS_MDLAPPS variables).  However, if I select "Browse" and load CivUstAT.ma, it loads with no errors.  I can then close IR and the custom tool and "load" button will work for the duration of the MS session.

Operation also appears perfectly normal when starting IR from the Start Menu shortcut(s).

Is there something I'm not doing properly to get the custom tool to work?

FYI, I'm running InRoads SS2 (08.11.07.536) in MS SS3 (08.11.09.292).