When a customer clicks the Edit icon (in both the defects & features) they receive the following error:

"Culture 'en' is a neutral culture. It cannot be used in formatting and parsing and therefore cannot be set as the thread's current culture."

 Other than the menus at the top of the screen, no other information is shown. Customer was given full permission to view and edit all content. Everything else appears to work ok.

Config error or bug? Any suggestions?