I just did a build of one of my DNN7 modules and now there are network errors loading any resources such as css or images. the response is an error page saying "Could not load file or assembly 'FiftyOne.Foundation' or one of its dependencies. The system cannot find the file specified."

I have never used the dll in my projects...I am totally lost as to why this came up... has anyone had this happen? how can fix?

I have uninstalled the module then grabbed an archived version from a point I know it was running and installed that one instead but I still get the error.