[gerthworm]

We get this error whenever the device isn't properly hooked up, or otherwise isn't visible to the RIO. Check out the web browser interface to your RIO and make sure it's showing up on CAN, the self-tests pass, etc.

As to shutting down the whole drivetrain, we've shown this year that lots of CAN timeouts add lots of delay to the user controls code (we were clocking over 200ms to execute our teleopPeriodic control code with CAN timeouts, and ~10ms without the timeouts). Depending on the rest of your code, its possible you could be hitting watchdogs or other timeouts that are disabling the drive? In any case I'd expect it to be a lot less responsive.