I assume you are using Mach3 because of Drivetest.exe. It sounds like you do not have your Port address right on the setup page.
On the computer. Go to "computer" right mouse click(RMB) "properties"
then in "device manager" find your parralel port, RMB "properties", the go to "resources" there sould be a 4 digit letter/number there. add this number to the port address in Mach. As I remember thats how it went anyway.
If that doesn.t work try the Mach forum or
Machsupport Forum - Index
Good luck
Mike