PHP头，内部服务器错误

我编写波纹管我自己的代码，我得到自动对焦*，我越来越厌倦这种每次荷兰国际集团内部服务器错误，请帮忙：PHP头，内部服务器错误

<? 
    function doer($str) 
    { 
     $d = base64_decode($str); 
     $a = explode('<||>',$d); 
     $v =array(
      'path' => $a[0], 
      'size' => $a[1], 
      'type' =>$a[2] 
     ); 
     return $v; 
    } 
    ?> 
    <? 
        header("Expires: Mon, 26 Jul 1997 05:00:00 GMT\n"); 
        header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
        $a= doer($_GET['d']); 
        $type = $a['type']; 
        header("Content-type: application/".$type.";\n"); //or yours? 
        header("Content-Transfer-Encoding: binary"); 
        $filename = $a['path']; 
        $len = $a['size']; 
        header("Content-Length: $len;\n"); 
        $outname="downfile.".$type; 
        header("Content-Disposition: attachment; filename=\"$outname\";\n\n"); 
        $filename = 'http://example.com/tst/'.$a['path']; 
        readfile($filename); 
    ?>

更多info：此脚本应放在（http://example.com/tst/）上，并且所有文件都存储在（http://example.com/tst/downloads）中。还没有.htaccess文件

来源

2010-06-21 kaveh taher