Make sure the $WAGLOBAL_Root_URL variable in the WA_Globals.php file is set properly.
If the User registration files are in a subfolder of your site, you need to include that in $WAGLOBAL_Root_URL. for example, if the URL to the user registration files is:
the $WAGLOBAL_Root_URL needs to be set as:
$WAGLOBAL_Root_URL = "http://www.mydomain.com/userRegistration/";