CSS menu works with Firefox, Opera, but not with IE

[eluser]mkmkmk[/eluser]
I played a little bit around. With this code also IE is running fine. But of course, it is a very ugly temporary solution:

Code:

$nix = $this->parser->parse('header', $data, TRUE);
$nix .= $this->parser->parse('temsilci_menu', $data, TRUE);
$nix .= $this->parser->parse('footer', $data, TRUE);
file_put_contents('nix123.php', $nix);
redirect('nix123.php');