I have not managed to get the game to run on 2560 x 1600. The installer .msi seems to do its work correctly, creating the expected files, for the 1.0c version that I downloaded... but no gameplay (menus work correctly).
Did you use the provided batch files? If so, strange, can you press printscreen and post the screenshot?
If you've ran it before with an old version, maybe you should delete an old 25601600.drs in the data folder, it doesn't re-create if it exists... So if you have a broken or old version, that might be the cause.
If you didn't use the provided batch file, I think you have to go to the 'options' screen every time and select (in your case) 1280x1024 again (change away to 800x600 then to 1280 again, in order for AoE to set everything up correctly. IF you use the batch file, it will FORCE to the right resolution, for me that works every time.
