[Mediawiki-l] Mailer configuration problem?

[Sandy Rozhon]

I implemented the extension NewUserNotif to send the Admin 
notification when a new user registers however I am now getting an 
error email with this subject line:  "Mail failure - rejected by 
local scanning code"

The returned mail seems to have the subject and body formed properly 
but the FROM address appears to be malformed in that it has 
wikiadmin at www.mydomain.com  <---- note the WWW that shouldn't appear 
in an e-mail address.

I can't figure out where Mediawiki's mailer or the NewUserNotif 
extension is getting that www from.  Maybe it doesn't even matter and 
there is some other problem?  The text of the error message is:

A message that you sent was rejected by the local scanning code that
checks incoming messages on this system. The following error was 
given:

  local configuration problem


Anybody have any idea what is going on here?  The extension itself 
seems to be working but I'm not receiving the notification cleanly.

Sandy