Error 1904: failed to register C:\Program Files\ArcGIS\Bin\MAgeometry.dll

Error Message

Attempting to install ArcGIS Military Analyst 9.0 on top of an ArcGIS Desktop 9.1 install produces the following error:

"Error 1904: failed to register C:\Program Files\ArcGIS\Bin\MAgeometry.dll"

Cause

While Military Analyst 9.0 can be installed on top of ArcGIS 9.1, the Geodesy functionality requires a file that is not included in ArcGIS 9.1.

Solution or Workaround