I recently downloaded a CRJ-700 aircraft from the Premaircraft Design website. I've got a couple of other models of this aircraft also downloaded from the same site. For some reason, this latest aircraft has a problem with brakes. The aircraft simply won't stop when I press the "trigger" button on the joystick. This button is assigned for brakes. The first time I tested out this aircraft, it wouldn't stop at all. The second time I tested out the aircraft with the groundhandling function enabled, I tested out the brakes just before the taxi run and the aircraft stopped in place. The aircraft was also able to stop with the groundhandling taxi speed function enabled -- if the aircraft taxi speed exceeded the established setting, the brakes would come on to slow down. Just as I approach the hold short line for the runway, I find that the aircraft won't stop. How is it possible for one aircraft to have this problem, but others of the same model work just fine. Can anyone help me fix this problem?