HTML Email Fails when Mailtype is set

[eluser]novice32[/eluser]
I have email.php under my config folder, so no initializing required. Although I have mailtype set to html, it receive emails with nonmame attachment.. that why I tried using

Code:

$this->email->initialize(array('mailtype' => 'html'));

I started another thread with this issue: http://ellislab.com/forums/viewthread/151416/