deleting mailboxes?

[Grant Beattie]

2.0.11/Solaris 7

root@wombat# grep admins /etc/imapd.conf
admins: cyrus

wombat> lam user.grant
anyone p
grant lrswipcda
cyrus d
wombat> dm user.grant
deletemailbox: Permission denied

What is causing this? How can I delete the mailbox?

g.