I think I solved the problem for 2.0.15 for me anyway!. It is difficult to explain. I am calling my folder testwrap so I will use that. The system was looking for a template file templates/testwrap_index.html in the normal /modules/testwrap/ directory instead of the trusted path directory. I copied the file /trusted_path/modules/templates/index.html to a new folder /modules/testwrap/templates/testwrap_index.html and that seemed to do the trick.

I looked at the oninstall and onupdate files and they seem to be the problem, but as I do not understand the templates I can't fix it!