[EricVanWyk]

You were correct in looking to see if you were shorting the 5V supply. Next time, take a look at the 5V LED.

You said the robot became disabled. Did the DS report "disabled" or did things stop moving?

A DS report of "disabled" would point me to a problem further "upstream". Perhaps your code around that particular switch does something funny - does it kill/starve the watchdog?

If it doesn't report "disabled", I'd examine and re-examine your wiring.