OK, so I spoke with my host provider and we verified that all of the IIS mappings are the same on both sites. The only “red flag” that stuck out for us is that the plugin works on the Parent site, but not the child site (Windows IIS latest version). Don’t know if that helps any but what I’m thinking is that my php.ini file isn’t pointing to the right storage directory.
Again, it’s working fine on the parent site and my child site pretty much duplicates that environment (except for the application paths, of course).