Var Plugin into template forumdisplay

[Asterix_ita]

I apologize for my bad English, we come to my problem

I created this plugin VB3

Hook: forum display_complete

if ($_SERVER['PATH_TRANSLATED'])
{
	$path = $_SERVER['PATH_TRANSLATED'];
}
else if ($_SERVER['SCRIPT_FILENAME'])
{
	$path = $_SERVER['SCRIPT_FILENAME'];
}
else
{
}

$path_head = substr($path, 0, (strlen($path) - 17));

$file = $path_head.'/head/'.$foruminfo[forumid].'.html';
    if(file_exists($file))
    {
      $head_forum = file_get_contents($file);
  }
  else  {
   
}

The result was called into the template via this code

 <if condition='$head_forum'>
<br />
$head_forum 
<br/>
<else />&nbsp;</if>
<!-- / Asterix special header -->

With vb4 I tried to change the code but not reported any results, the plug remained unchanged.

 <!-- Asterix Special header -->
<vb:if condition="$head_forum">

{vb:raw head_forum }

<vb:else />{vb:raw file} Pippo prova&nbsp;</vb:if>
<!-- / Asterix Special header -->

The $head_forum is no longer being charged and even the variable $ file. Why?

Thanks