1- your question is posted as a reply in an existing thread, so likely many viewers on the forum may not see it. Should have been started as a new topic.
2- DONT USE ALL CAPS PLEASE!
3-What computer model/OS version, etc.?
It sounds like you have not set up your monitors in the “Displays” pane in System Prefs. You should also have a separate ATI Displays Pref Pane to tell the monitor you are sending it DVI and not analog.
Also sounds like you were trying to set video resolution in FCP to that of your monitor, not a video editing codec.