Post By Mail Error [13}] Yahoo

I am using the default WordPress installation as installed by Yahoo and am trying to use Post by Email. I have tried goin at it bith using wp-mail.php and the Postie add in. Same Error reported under both scenarios:

Unable to connect. The server said – POP3 connect: Error [13] [Permission denied]
Try putting in your full email address as a userid and try again.

Yahoo terchnical support keeps trying to say it is an error in WordPress (which conveniently for them gets them off the hook on doing anything. Yhey take credit for offering wordpress and even have a hlep article on how to set up email blogging, but when it gets down to “do” they thriw up their hands). They told me to contact WordPress hence this post.
(A) Has anyone else encountered and solved tthis error
(B) Has anyone gotten this feature to work with Yahoo

I would really appreciate any help. I am trying to set up a website with wordpress as a framework for non-technical users so the post by email feature is ideal for them and I would really like to get it runnign.

Thanks in Advance

Neil