I had the same problem on my new installation (1.2.2). After a quick trace in the code I could find nothing wrong there. Then I tried mailing using the “mail” command on a console.
( type “mail [email protected]” <enter> “some text” and ctrl-d ctrl-d. )
This also didn’t work indicating that wordpress was not the problem. It turned out to be a rights issue on the dir where the mail command drops the mail.
Hope this can help somebody.