Change text on "Create new Account" button makes administration created user registration fail
That code works without a problem for me. I hope you didn't change the code in Drupal's user module directly?

You should make this change by implementing hook_form_alter() in your own custom module or theme. 

function MODULENAME_form_user_register_form_alter(&amp;$form, $form_state, $form_id) {
     //your changes here
   }