You need to make sure that your display options are set the same as the full screen game options so that you don't get the full screen error. This guide here can explain how to set a custom resolution for your game: http://forums.aeriagames.com/viewtopic.php?t=50913
You could also try to use a smaller resolution. It's not a Windows 7 64 bit issue as it just took adjusting and its the OS that I use currently.
Just an FYI: It's best advised to start a new topic than necroing a thread from at least 2 years ago. It's a bit frowned upon and could get one into trouble.
Good luck though resolving your issue.