Sorry, unable to edit..
Didn't think it would work but a lot of things in scripting are trial and error so tried the following change -
header('Location: http://www.mydomain.com/success.php?user=$fuser');
to
header("Location: http://www.mydomain.com/success.php?user=$fuser");
(double quotations instead of single i.e. " instead of ' around location) Did the trick

Thank you very much for this script. Without it my whole model wouldn't work. Still a lot of implamentation to go but I think I have modified it enough to do what I need.
If I make any money from this project I'm working on donations will be made I promise

EDIT: Already added username character validation and password verification. Just need to add some sort of validation check to make sure no duplicate usernames are submitted. Will post modifications and brief documentation when everything is done, with a link to my site if thats allowed. Never know who it might help some day in the future.