dovecot - Nov 2005 - Error: Mailbox isn't a valid mbox file

Hello all,

I have successfully migrated from pop3d to dovecot.

Now, I am having users call in unable to pop (prompted with a user/pass
login).  OE shows this in the error box:

Mailbox isn't a valid mbox file.

I am able to log into the box using Webmail.

Any suggestions?

Cliff