Do you have zoom mapped to an analog controller?
Mapping zoom to an analog control is the only way I know of to make Z not work. You might check your axis mapping if nothing else works.
Make sure you don't have "field of view" assigned to an analog joystick axis in the aces high joystick settings.
OK OK OK, I guess I'll go check, Even though I NEVER ASSIGNED ONE so it CAN'T BE THAT.
*runs off and checks*
Hunh. Lookit that. Assigned to the ministick X-axis for some reason. I guess I shoulda listened the first time.
BB