[eluser]bretticus[/eluser]
[quote author="peter222" date="1287093262"]The problem is than I can't find it by text in whole CI source. I don't know where it comes from. My Thunderbird shows this header in source.[/quote]
Look into the php.ini settings. Perhaps, this is shared hosting and there's nothing you can do as it's a "server thing." You might want to contact support.