Fatal error: Call to undefined function:

[Anon]

I am receiving A call to undefined function error. Please look at the following code and let me know any thoughts on the problem.

global $my_session_save_path;
$my_session_save_path = ("/usr/local/plesk/apache/vhosts/yourdomain.com/httpdocs/"); /wasn't sure if the last slash was needed. I want the directory in side the httpdocs directory /

function get_sessionfile_name_internal()
{
if( !$this->id ) return '';
return $session_save_path()."/sse_{$this->id}";
}

function garbage_collection_internal()
{
//limit garbage collection resource usage.
if( rand(1, 100) > $this->gc_probability )
return false;

  dbg("garbage_collection_internal started");
  $dir = dir($session_save_path()); /* This is Line 165*/
  while($entry = $dir->read()) 
  {
    if( strncmp($entry, 'sse_', 4)==0 )
    {
       $fnam = $session_save_path()."/$entry";
       $f  = fopen($fnam, 'r');
       if( $f ) 
       {
          $l1 = fgets($f, 100);
          $l2 = fgets($f, 100);
          fclose($f);
          $this->check_expire_and_delete($l1,$l2,$fnam);
       }
    }
  }//for each file in the dir.
  $dir->close();

}

[Anon]

If I try removing the inner () from Line 165 I receive this error.

Warning: OpenDir: No such file or directory (errno 2) in ses.php on line 165

Fatal error: Call to a member function on a non-object in ses.php on line 166

Any help is greatly appreciated.

Thanks,
Chris