Found a work around
Thanks for the reply. The problem was on the splash screen before the activation appeared.
I tried the FAQ tips on 'Common Installation Issues', this really messed things up and Dreamweaver wouldn't even launch because of an error in 'DocumentEncoding.js'.
I re-installed the validation toolkit in Extension Manager and Dreamweaver would then launch but the toolkit still would not work. Finally I un-installed extensions one at a time and when the Google Pro Maps extension was off the toolkit starting working. So I guess that's better than nothing.