[Logician]

This is because you inserted the hack code into the wrong section in the first place. Now follow me and please proceed carefully:
1- Revert back to your original newthread.php
2- find:

PHP Code:

  if ($postpoll) {
         $visible = 0;
      } 


3- Delete the section starting from there until :

PHP Code:

 // update forum stuff 


4- Now insert this code into the part you deleted

(Btw. please remove your file from the post above. Site rules do not allow posting of entire vb files here.)