mail() returns false but e-mail is sent ?

Hello, I'm wondering about the behavior of the mail() function. $sent = mail($destination, $subject, $content, $headers); I use some optional header parameters: "From:admin@website.tld\r\nMIME-Version: 1.0\r\nContent-Type: text/plain; charset=ISO-8859-1\r\nContent-Transfer-Encoding: quoted-printable\r\n". Can that be source of error? I can see no error in the apache error_log. I have special caracters in the subject line, which are converted first on php side to comply with standard. Here also, no error on apache error_log. The result of mail() is false but the e-mail is sent! Returning true, but e-mail doesn't reach destination can make sense; in this case, it's strange, isn't it? I'm using PHP v. 5.04 on a Linux Fedora Core 4 distri with Postfix 2.2.2. I'd be glad if somebody could explain me what to do in order to get correct response when e-mail is passed to MTA... Thanks, LS -- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer