Here are some things you have to do to make this work:
* Change the file type of MultiFinder to APPL. HyperCard only runs applications (or documents belonging to applications) when you use HyperTalk's Open command. Changing MultiFinder's file type to APPL makes it an 'application'.
* Make sure that no INITs are loaded if you want A/UX to be run. The sash application that launches A/UX 1.0 or 1.0.1 does not coexist with most INITs.
* Make sure that the launch command in the sash application is configured to launch from the proper drive if you are using more than one hard disk on this machine.
* Within HyperCard, you need to decide whether you will include a card on the Home Stack that does the launch, or if you will use the start-up script in the Home stack to open another stack that does the launching.