When Standalone Workflow Manager is started and logged into, the following error is thrown:
This is caused by bug CLS-54060, which has not been resolved in any ArcFM releases. This error only occurs on client machines on which ArcGIS Desktop is not installed.
The workaround is to install ArcGIS Desktop or ArcGIS Engine. The ArcGIS Engine installation does not add any Start Menu items, so it may be preferred over ArcGIS Desktop.