PHP fsockopen form submissions from multiple domains

PHP fsockopen form submissions from multiple domains

I have two domains and have been using the standard source copy/paste under 'embed options' on one of them for years with success.  But now I'd like to use the same form on another domain I own on the same server.  However in this case I'm using PHP and fsockopen calls on the server to attempt to relay the form data.  This part isn't going so well, I'm not having any success trying to submit the post.

Q: are these web forms locked down to only accept posts from predetermined referers?  If so how do I get around this without reinventing the wheel?  If not where can I get my hands on some proper error messages to help me nail down what I'm doing wrong?

Regards,

Michael