No I never used the batch link check for their site. I just checked for a phrase on the download page to confirm the link was working on my link checker. I've never had the need to do large amount of back link checks for uploading.com. Only Hotfile and Rapidshare.

Have you CURLOPT_FOLLOWLOCATION and CURLOPT_RETURNTRANSFER?

EDIT: maybe this should be moved to Technical Help Desk Support