[Dovecot] ERROR : Connection dropped by imap-server.

hi there,

i'm trying to setup dovecot with squirrel mail at the moment and i'm getting this error message

ERROR: ERROR : Could not complete request. Query: CREATE "Sent" Reason Given: Permission denied

ERROR: ERROR : Connection dropped by imap-server. Query: SELECT "INBOX"

can someone tell me what this means? and what folders i have to change the permissions on?

this is out of my /etc/dovecot.conf file if it helps

default_mail_env = mbox:/var/mail/%u:mbox:~/mail/