email subject in utf 8 is not work!

[eluser]Unknown[/eluser]
Just to let you all know.
All emails i sended from CI had '=?UTF-8?B?' as subject, i diged the wrong direction so it costed me "some" time to find out that the problem was that i sended an empty string to the subject (because of empty lang file).
Case solved
Cheers,
Gerard