Here are some more details about how I got to this point.
I installed DMX early this year, and kept it updated through version 5.2.7. At that point, I had to create several demonstration instances of our product that uses DMX as its file repository. To create those, I backed up then restored my database (including all my tables, etc. and all data from 3rd party modules that we are using such as DMX) to a new schema/new dbo.
I copied all files from my web site to another location and set up a directory under IIS so that I could reference the new copy as its own unique instance.
All that worked fine, giving my demonstration versions an exact copy of what my development environment looked like as of that point in time.
Now I want to update my development version and the demo versions to the latest DMX. The development site updates fine, but any demo site gets the error I noted above and the installation halts. It seems as though DMX "knows" where it was installed initially and my derivative versions can't be updated.
So, what do I need to do to make these environments able to be updated?
Many thanks,
Bruce