Just encountered this for the first time just a while ago. Was flying FSX on VATSIM with vPilot on a KJAX - KDTW flight. Everything was fine until I was in Atlanta Center territory and FSX crashed. Restarted everything, logged back onto vPilot and FSX crashed again. Restart once more without vPilot, everything working just fine.
I uninstalled vPilot and reinstalled it, still causing FSX to crash. Looked in the event log, vPilot is messing with the sim1.dll somehow as that is the cause of FSX crashing when vPilot is running.
Has anyone else had this issue before? Also posted on VATSIM forums in case anyone might know something as well.