I agree with you that the format of the typical LWP response is something like you have just stated. But the error message that I am forwarding in my posts is the status_line of the response object, not that of the user agent object.
Far from me the idea of wasting your time (and mine) by faking the messages... I just copied and pasted them.
Anycase I've disabled SELinux and the problem has been solved. But now another problem arises: should I leave SELinux disabled ???
Thanks for taking the time to respond to me. A.