You mentioned above that it had been dropped. It is therefore possible that there is a bad connection somewhere either to the diode or the driver, but it is also possible that the bond wires in the diode may be damaged. If the latter were the case the laser may turn on by shaking or rotating it due to an intermittent contact within the diode.
Who did you buy it from? Perhaps they can offer to fix it. If you wanted to try yourself youll need to take it apart and use a DMM to test the connections. With C6's you should be careful when removing the retaining ring on the end. Make sure you hold the heatsink with your fingers so it cant rotate when you unscrew the ring. If the heasink rotates you run the risk of ripping off the diode pins. :beer:
Edit: did you check your battery too?