unexpunge broken?

[C.K]

Is here anyone who ca ntell me how unexpunge works?

i have delayed in imapd.conf
expunge_mode: delayed

and cyrus.conf
delprune        cmd="cyr_expire -E 6" at=0100
expunge         cmd="cyr_expire -X 8" at=0300

but when i try the commands in any form i get errors like this,

mail2# su cyrus -c "/usr/cyrus/bin/unexpunge -l user/demo at inkorgen.com"
mail2# tail /var/log/imapd.log

Aug 21 17:57:50 mail2 unexpunge[47669]: unable to open/lock mailbox (null)

whatever flag i give unexpunge i get the same error...

How is the syntax to restore mail this way?

/Calvin Klein