If the URL that you are seeing in the email is:
users_Confirm...R8bjdqQp6Bg606
Then you probably did not update your WA_Globals.php file after you updated it to:
$WAGLOBAL_Root_URL = "http://www.vbsa.org.au/Bus_Registration/" ;
The url you should see in the email should look something like this:
users_Confirm...R8bjdqQp6Bg606