[_ck_]

Headers already sent is a useless error in itself, it’s always the result of another error (unless the very rare case someone meant to send a custom header of some kind).

In this case at least you posted the real error:

Warning: parse_url(http://#postform) [function.parse-url]

Any chance you are testing this on a localhost or something like that?

Kind of a strange error that it’s getting a bad url like like, there’s no domain name at all.