Reference Notices -- Urgent

I'm getting the following notices: Notice: Only variables should be assigned by reference in .... Notice: Only variable references should be returned by reference in .... The code in question comes from PayPal (their CC processing API,) so modifying it to correct the reference issues is *not* an option. On the actual implementation server (PHP 4.4.1), I am not receiving these errors. On my test server (also 4.4.1), I am. I have run phpinfo() on both servers and carefully compared the output; as far as I can tell they are configured identically. I really need to be able to successfully run this code on my test server, and I am now baffled as to how to eliminate these notices. Both servers have the same PHP version and configuration; why are they behaving differently? I have searched and searched for an answer to this, and need help urgently.

                             Sincerely,
                               Todd Brown