php上传附件老是失败，我是用别人写的附件上传下载程序，请大哥门帮帮忙

下面这段是upload.php里的代码，请问是什么问题！！
$a=strtolower(fileext($_FILES['file']['name']));if(!in_array(strtolower(fileext($_FILES['file']['name'])),$type))
{
$text=implode(",",$type);
echo "Allowed  file type  : ",$text,"<br>";
}
else
{
$filename=explode(".",$_FILES['file']['name']);
do{
$filename[0]=random(10); 
$name=implode(".",$filename);
$name1=$name.".file";
$uploadfile=$uploaddir.$name1;}
while(file_exists($uploadfile));if (move_uploaded_file($_FILES['file']['tmp_name'],$uploadfile)) {
$db=new db;
$db->connect($dbhost, $dbuser, $dbpwd, $dbname);
$sql="insert into list (code,file) values ('".$filename[0]."','".$name1."')";if($db->query($sql))
{echo "<center>The fast download URL: <p>".$patch."link.php?ref=",$filename[0],"</center><p><hr>";}
else{echo "failed";}