I have the same problem. While all other System Commands work, I can't get the "Sleep-Command" to work. I don't know when this startet or if it's related to an update, but please help me to solve that problem. The Console tells me: System Events[2719]: A call to OSACopyScriptingDefinition() by NSScriptSuiteRegistry returned an error. Is this application's OSAScriptingDefinition Info.plist entry valid? If its value is 'dynamic', is there an 'ascr'/'gsdf' Apple event handler registered?