ผม upload file แบบเปลี่ยนชื่อไฟล์ บน server ไม่ได้ครับ

<form enctype="multipart/form-data" method="post" action="direc2.php">
  Name: <input type="text" name="name" /><br><br>
Select file 
<input name="ufile" type="file" id="ufile" size="30" /><br /><br />
<input type="submit" name="upload" value="submit"  />
</form>

// Standard
<?php
$file_tmp=$HTTP_POST_FILES['ufile']['tmp_name'];
$file_name=$HTTP_POST_FILES['ufile']['name'];
$explode=explode(".",$file_name);
$new_file_name=$explode[0]."-".rand().".".$explode[1]; // rename and protech refresh cache
$path= "uploads/".$new_file_name;
	if($ufile != ""){
		if(copy($file_tmp,$path)){
			echo "Successful<BR/>"; 
		}else{
			echo "Error";
		}
	}
?>

// muti array
<?php
$file_tmp=$HTTP_POST_FILES['ufile']['tmp_name'];
$file_name=$HTTP_POST_FILES['ufile']['name'];

for($i=0;$i<count($file_name);$i++){
	$explode=explode(".",$file_name[$i]);
	$new_file_name=$explode[0]."-".rand().".".$explode[1]; // rename and protech refresh cache
	$path= "uploads/".$new_file_name;
	if(copy($file_tmp,$path)){
		echo "Successful $i<BR/>"; 
	}else{
		echo "Error";
	}
}
?>