Mutt lock sent

[Larry Fletcher <de-42@extra.lafn.org>]

Since upgrading to Etch I've started receiving the following
messages from Anacron:

    Subject: Anacron job 'cron.daily' on lotek.lafn.org

    /etc/cron.daily/anacron-sys:
    Couldn't lock /sent

    Could not send the message.
    /

I eventually traced this to emails that mutt sends from the
command line or scripts.  The emails are sent, but they are also
added to file in the ~ directory called "sent" and a zero byte
file is created in the / directory.

Where possible I have changed to mailx, but in some cases
I need to use mutt.  Does anyone know how to fix this problem?

Thanks for any help,

  Larry