After viewing the register page on your website, I found in the source code :
For Button :
<input type='submit' name='register' value='' class='button' />
No Value specified. Please enter the value to be shown on button.
For Validation Code :
<td valign='top' class='tbl'></td>
No Text between the td tags. There should exist Validation Code: by default;
You should check for these codes in your register.php and should update it.
If the locale already exist for the value and the validation text, then try checking those locale values in the files.