I didn't get this error here, however I recieved the exact same error when I used my german "..@googlemail.com" mail address to register on appengine. After cha

I didn't get this error here, however I recieved the exact same error when I used my german "..@googlemail.com" mail address to register on appengine. After changing it to "..@gmail.com" it worked. If you are german, you could try that as well.