I followed these instructions to the letter and I'm still asked to insert original disk instead of backup:
1] Install the game and apply the Update v1.05.
2] Get the latest version of Daemon Tools (v4.08HE), mount the Mini-Image FPS_EAW1.mds) and enable all emulation options in Daemon Tools.
3] Download the latest version of YASU (v1.07) and execute it. Press Ok.
4] Play the game, have fun...
and I STIIL get this message -
THIS IS DRIVING ME CRAZY!
I also tried a dozen other programs instead of YASU, nothing worked.