PHP upload檔案問題

[kkwai]

move_uploaded_file($_FILES["product_pic"]["tmp_name"],"productimg\\".$_FILES["product_pic"]["name"]);

Warning: move_uploaded_file(productimg\aa.jpg) [function.move-uploaded-file]: failed to open stream: Permission denied in E:\inetpub\vhosts\wildka.com\httpdocs\admin\add.php on line 6

Warning: move_uploaded_file() [function.move-uploaded-file]: Unable to move 'C:\WINDOWS\Temp\php206A.tmp' to 'productimg\aa.jpg' in E:\inetpub\vhosts\wildka.com\httpdocs\admin\add.php on line 6

有什麼問題，怎樣才能upload？