哪位高手帮我看看我这个程序咋调试不出来

<?PHP

function directory_size($directory){

$directorysize=0;

//open the directory and read its contents
if ($dh=@open($directory)){
//iterate through each directory entry
while($filename=readdir($dh)){

//fileter out unwanted directory entries
if ($filename !="."&& $filename !=".."){
//file ,so determine size and add to total
if (is_file($directory."/".$filename))
$directorysize+=file_size($directory."/".$filename);
//new directory ,so initiate recuresion .*/
if (is_dir($directory."/".$filename))
$directorysize+=directory_size($directory."/".$filename);
}
}
}
@closeddir($dh);
return $directorysize;
} #end directory_size()

$directory="D:\AppServ\www";
$totalsize=round((directory_size($directory)/1048576),2);
printf("directory %s: %f MB",$directory,$totalsize);
?>