Hello again list!

I am configuring a server running Dovecot 2.2.15 (Pigeonhole 0.4.6), and I am having an issue with Sieve scripts where I cannot sort messages into a subfolder of a mailbox. An email which is matched by the following script:

require "fileinto"; if header :contains "Subject" "[SORT ME]" { fileinto "INBOX.Sorted"; }

Yields the following error:

Jul 16 18:54:46 smtp dovecot: lmtp(james@lottspot.vpn): Error: DiJmNGZgqFWLFAEANWXNPw: sieve: msgid=<4973528.yvy4Yu8Tt4@arch_project>: failed to store into mailbox 'INBOX.Sorted': Character not allowed in mailbox name: '.'

As far as I can tell based on the Sieve usage page in the wiki (http://wiki2.dovecot.org/Pigeonhole/Sieve/Usage), this is *supposed* to work. I have included my namespace configuration below, but if anyone wants the whole doveconf -n, I will gladly provide it. Thanks in advance for any help!

namespace inbox { type = private separator = / prefix = inbox = yes mailbox Drafts { auto = subscribe special_use = \Drafts } mailbox Sent { auto = subscribe special_use = \Sent } mailbox Spam { auto = subscribe special_use = \Junk } mailbox Trash { auto = subscribe special_use = \Trash } } namespace { type = shared separator = / prefix = shared/%%d/%%n/ location = maildir:/home/%%d/%%n/mail:INDEX=~/indexes/%%d/%%n:INDEXPVT=~/indexes/%%d/%%n subscriptions = no list = children }