KMail cannot create top-level folder

[Timothy Murphy]

I am running KMail on my laptop
taking email from dovecot on my server.

I am unable to create a top-level folder with KMail -
that is, on the same level as Inbox 
(corresponding to ~/Maildir/cur on the server).

I was previously able to create such folders;
I'm not quite sure when it ceased to be possible.

I think I could create the folder by creating a sub-directory
to ~/Maildir/ on the server.
Or I could install KMail on the server, and do it that way.
But how exactly is one meant to do this?

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin 2, Ireland