Help, my late-2011 MBP won't connect to my Apple Cinema HD Display.

I recently purchased the Apple-brand DVI-to-Thunderbolt adapter to connect my early-2011 MacBook Pro to a 27" Apple Cinema HD Display. The display turns on, and the USB devices connected to the display work with my MBP, but there is no image on the screen. Under "About this Mac -> System Report -> Thunderbolt", the Thunderbolt status says, "no devices connected". The display has been tested and works on a different computer.