I have this exact same problem:
I'm using a brand-new Arduino Uno, I'm able to run the ASCII chart sketch on it no problem. When I run the shield test sketch (using either the red-label init line or the green-label one, doesn't matter) the joystick prints its status to the serial port but the screen is just solid white.
Here are links to some pictures of my solder joints; I think they're fine because the backlight comes on and the joystick works: http://www.flickr.com/photos/84998402@N ... 985017564/
There's nothing obviously wrong with the screen, it's not taped very well on to the PCB but the ribbon cable looks fine.
So, is there anything I'm doing wrong, or can I get a replacement shield? Thanks!