HTML Email Fails when Mailtype is set

[eluser]bafadam[/eluser]
I can send a text e-mail just fine, but when I try and initialize the html setting for the e-mail, I get a bunch of errors.

Here's the code that doesn't work, though if you remove the third line, it works just fine (obviously when the message and all that other stuff is set.

Code:

$this->load->library('email');
$this->email->set_newline("\r\n");
$this->email->initialize(array('mailtype' => 'html'));

It tosses out this:
A PHP Error was encountered

Severity: Warning

Message: mail() [function.mail]: Bad parameters to mail() function, mail not sent.

Filename: libraries/Email.php

Line Number: 1519