I don't have any error during the intstallation and adding products. There is just nothing happened to my facebook page after added products. Ok, here was my steps:
1. created a page in facebook
2. i found out now how to setup a username in facebook too
3. install autoFacebook lite, select my page and enter the URL (see the attachment)
4. past the page id to $app_id in update_product.php (located at /admin/includes/modules)
5. i have left out these variables blank ( $app_secret, $page_id, $page_token, $store_name, $store_url, $cur, $new_message ) in update_product.php (is that correct? or should i delete them?)
6. i have also uploaded facebook.php and facebook_authorization.php to my server (is it necessary?)

Please tell me if I have done anything incorrectly. Thanks.