I recently redone some changed, I've found if I used the pi with the zwave controller to run the script to turn off my lights I don't get the error/crash, but if I run the same script from my master.it give the error/crashes. Turning the lights on from the master doesn't cause any issues.

I been having the same issue with my pi running the zwave domoticz server, my other 1 isn't have any issues which only has the piface board isn't having any issues. Only been happening since the latest update.