@cscheiene ’s code is a DTH, not a smartapp. The message you got can happen if you add a DTH in as a smartapp.
Did you put it into “My Device Handlers” in the IDE?
Or were you having problems with the original smartapp from the manufacturer?
In either case, be aware that since the groovy cloud will be turned off in a few months, both the smartapp and the DTH will stop working when that happens. So you might want to check with the device manufacturer to see if they are planning to provide an integration to the new SmartThings architecture.
