No Data Received - Localhost editing problems

I recently copied a site from the server to localhost (wamp). I can make edits live (but that's scary! so I took it offline to wamp). The site is fine and I can log in but I cannot edit anything. When I click on the Admin panel above the overlay remains but nothing happens. If I click again I get 'No Data Received. Unable to load the webpage because the server sent no data.'
Anybody experienced this or know how to fix access to edit within admin?