I also get this error message, without having Validation Toolkit installed.
Installing SA2 has caused me so many problems and setbacks now its untrue.
This product is absolutely not ready for the commercial market as far as us MAC users go.
For MAC users I suggest you wait until the dot release - whilst Ray was excellent in helping me out the other night he was remoting to my machine for, quite literally hours, recoding the JS files within the extension, it's just not ready as a commercial extension.