Ahhh yes I remember the other trick now!
There is a terrible bug in all versions of Picasso96OS and CybergrafxOS that I have ever tested. You can't reliably run AmigaOS software that opens an AmigaOS screen while any P96 or CGX screen is already open.
You can change your workbench to an AGA mode then run SCALA and it might work.
Make sure you have no CGX screens open for this trick to work. No web browser, no text editor, etc.