With this one - as the form action is set to the user_Registration.php page (i.e. itself) where you have:
should really be
I can't complete the form at the time of this posting- as the 'State' dropdown list isn't populated, so returns an error. Assuming that the other paths are correct (error & success, WA files) changing the line above should take you forward a bit.
Perhaps you could change the above line - for the purposes of testing this example - and put some values in the 'State' selector so someone can have another look at it?
This suggested in preparation for Jason sorting out the clever stuff.