[1.09t] White Screen when starting new game

I see several posts about the game crashing with 1.09s, but in my case the game doesn't crash. Instead, the screen is just all white so I can't see the cloth map, units, or anything else other than the basic UI. I can hit Esc and the window appears with Save, Load, Options, Exit to Main Menu, etc. so I can exit to the main menu and then exit the game. I tried uninstalling the game and reinstalling it, but the white screen still occurs.

My video card is an ATI Radeon 5870 1GB and this is on Windows 7 64-bit.