Cyrus Cannot Delete Mailbox

[adam at morrison-ind.com]

I've got my Cyrus IMAP test install up and flying (temporarily on port 7777 so
as not to bother the UW IMAP server currently in use).  It is fast and works
great.  But I've got one problem.  I can't delete mail boxes.

$cyradm --user cyrus --server sardine --auth plain --port 7777
sardine>lm
...
user.ksikkema.steelcase (\HasNoChildren)                               
user.mhuisman (\HasNoChildren)                                         
sardine> dm user.ksikkema.steelcase
deletemailbox: Permission denied
sardine> setacl user.ksikkema.steelcase cyrus ad
sardine> dm user.ksikkema.steelcase
deletemailbox: Permission denied

User "cyrus" has god-like power, yes?  Any tips on my I can't remove boxes would
be much appreciated.