Doors Won't Open

For some reason I am unable to open doors, hatches, etc. on planes for which that is supposed to be possible. I believe I'm supposed to hit "Control + E (simultaneously)" and then 2, 3, or 4. But nothing happens when I do that.
Could I have some setting wrong somewhere in the "Settings" section of FS9? Is there someplace in the aircraft.cfg file that I can check for an error?
Does anyone else experience this problem?
Could I have some setting wrong somewhere in the "Settings" section of FS9? Is there someplace in the aircraft.cfg file that I can check for an error?
Does anyone else experience this problem?