I have just worked out what was wrong and have sorted it.

It was somthing to do with this section

To amend the <YOUR ADMIN DIRECTORY>/includes/functions/html_output.php by hand is fairly straightforward.

However before attempting to edit this file, please make sure you have a secure backup of the original version.
Open the file in an editor and find the function "zen_draw_form"

The last line of this function is

return $form;
Just before that line add another line as below

$form .= '<input type="hidden" name="securityToken" value="' . $_SESSION['securityToken'] . '" />';
You can then save the file.

I changed it as it says here and that is what caused the problem as I have just overwritten the whole PHP in functions and it is now working as it should.
I do hope this helps others and thanks for your help Kuroi