[Q] [PHP]

I am trying to access a CGI on another site using a PHP header call. It gives me a invalid access error on the cgi servers end, almost like it wont let me in the door. For example, I can use a simple html form to get to: http://www.free-banners.com/cgi-bin/fb/submit/reg.cgi however when I header ("Location: http://www.free-banners.com/cgi-bin/fb/submit/reg.cgi?XXX=$XXX") I get the error, where XXX=$XXX is the list of variables. I am pretty positive that I have all the variables in total. There are 16 in the form code including hidden and I am sending those using PHP. Any ideas? Is there a way that the CGI may know it isnt a direct request and that I am going through this other method? It should still provide the same result.. Thanks