To simplify the issue, I have made a simple html file with a line of text in it. No tags. I placed this in a folder under DesktopModules called MLSMap. There are no other files in that folder.

I then created a new module definition with module name, folder name, friendly name and description all set to MLSMap. I save the module details and try to "Create Module Package", checking on the option to create a .dnn manifest file. I did not change the file name provided by default. I receive the message "A critical error has occurred. Empty path name is not legal."

I've tried with DNN 4.0.0 and 4.0.9.

Thanks. Unfortunately, the client I'm working with uses an older version of DNN and upgrading would be an issue for them.

However, I did manage to find a way to get my module in place via another method, so while I still don't know why the packaging bombs, it's not hindering me any longer at least.