Tools | FREE Hide Errormessage
Widget OPTIONS: This widget hides the annoying message: “Some files on the server may be missing or incorrect. Clear Browser cache and try again. If the problem persists please contact website author.“
It does NOT solve the muse problem, but it hides the message.
Just place the widget somewhere on your page. It is recommended that you use this widget only for your production site, where you or clients are encountering the errors. You should not use the widget for your sites in the testing environment.