Mining with the Prospector. When stationary and beginning to mine, the Prospector tends to creep forward, with the ROC you can turn the drive off, so is there a similar option for the Prospector?
AAAAND, make sure that you've calibrated it in Windows. Honest, I'm not trying to sound like tech support, but this is pretty common...check your settings and and add a good chunk of deadzone on your controller, if that fixes it, you know the issue.