Since MyExpose is apparently a third-party program, you should check
with its tech support. The "flip 3D" natively available in Aero (and no,
I don't know whether it is supported in 64-bit because I don't have a
64-bit system) is MS's copy of the real Expose. You might want to try it.
Or perhaps your video card doesn't support Aero? Are you using the
latest 64-bit drivers from your video card maker?