probably your end..I use a HIS 4870 catalyst 8.12
What brand do you've? If the game flickers, it might mean that it's constantly switching power consumption mode. (changing between 2d & 3d mode).
In ATI catalyst go to ATI overdrive. I think you've to activate it (click the padlock). But you don't have to use it.
it says "Current Values" when playing Eternal Eden see if these clock numbers change. if it constantly changes back & forth flicker might occour. I've this issue when watching movies & the screen is completely black (such as before the title, or after the credits). Power consumption will switch back n forth between 2d & 3d mode.
Eternal Eden is all 2d, so catalyst might believe you're just at the desktop (not playing a game).
it's just a theory.
Did you try the set AA, AAA, AF all to application controlled? You won't need them in Eternal Eden anyway, because it's all 2d. Set V-sync to ON.
In Eternal Eden press F1, choose the option "reduce screen flicker". I never had to use this, but maybe it will fix your issue?