I'm having this problem as well. On 1680x1050.
Window'd mode works fine I adjusted the refresh rating to 59 which I had before 1.2 which I needed to run to play the game on fullscreen. I followed the same steps and when I go to enable full screen with my correct settings it goes back to out of range again. Why is this happening? I checked the client settings file everything seems fine in there..unless I'm overlooking something to adjust.
Please help cause I am excited and want to thoroughly enjoy 1.2!