Just try it without this...
header("HTTP/1.1 200 OK");
If it works then no worries, if it doesnt then place it in
If I remember correctly unless their is an error return ok and run the script or some shit. IE if their is an error 404 it will return 200 ok and proceed to the script. Or some shit like that. Ofcourse I could be wrong
TheDoc
http://www.largecash.com