Yes, I ALWAYS uninstall old versions of extensions. I learned that lesson a number of years ago. I did check your link, and I've had to do that fix several times already (like with EVERY WebAssist update). I also have a PPC based Mac that I am going to test and see if it happens there too. I'll keep you posted. Thanks for your suggestion.
PS- got it to work on the PPC (although it had the same wacs wizard js error that involved yet MORE trouble-shooting). It seems from the number of posts regarding v1.0.7 there is something going on.