Can't send email

It seems like a bug has existed for a long time since 1.6

After upgrade to 1.6 from 1.5.3 several days ago, I found moodle can't send email. In the send email page, after submiting and waiting for a long time, I got the message:

Fatal error: Maximum execution time of 30 seconds exceeded in /........./moodle/lib/textlib.class.php on line 215

The line number is not a constant. Sometimes it is in function strlen and substr.

I traced the code and found that moodle went into a infinite loop in function CreateHeader() of phpmailer.

It's a fatal bug but I don't know why nobody reported it. Only me meet it?