Updating an existing PHP script -

I have a site that enables users to download and save flash videos from [YouTube][1]. This is done by a PHP-script. The script doesn't work anymore - I guess YouTube have done some changes on their site, and that is probably the problem. There are sites like mine who still works with YouTube. As I'm clueless when it comes to PHP, I need someone to fix the existing PHP script so that it will work with YouTube again. [This is the part of the site][2] that does not longer work. I will of course provide you with the existing PHP script.