Try the current build. Previously you had to replace the jre folder inside the app's Contents/Resources folder with a downloaded jre (I made a post on this along with setting the execute permission the app's executable in order to launch it). To get the app to work you still need to replace the jre but the recent Mac build did fix the "DesktopLauncher quit" issue when double clicking the jar file but it doesn't seem to be work consistently (not sure why though)