osCommerce PHP5 tauglich machen

[elexis_linux]

fatal error: Cannot re-assign $this in ....\catalog\admin\includes\classes\upload.php on line 31

Ursache: PHP5

in:
/admin/includes/classes/upload.php

alt:
// self destruct
$this = null;

neu:
// self destruct
// $this = null;
unset($this);