[ingo] Create New Folder not working

[steti at monmouth.com]

Hello,

I'm setting up a new installation of Horde Groupware Webmail Edition,  
and I'm having trouble getting the "Create New Folder" function in  
ingo working correctly.  For example, I create a new filter rule as  
follows:

Rule name: Test rule
Subject contains: test
Deliver to folder...
I select the "Create new folder" option from the select menu, and I  
get a Javascript popup asking for the new folder name.  I input the  
name "test" (without the quotes), and the select menu updates to read  
"Create new folder [test]".

However, the "test" folder is never created.  If I look at the Sieve  
script that was uploaded to the server, the rule reads

fileinto "Create new folder [test]";

When mail comes into the account matching this rule, I get the  
following error from Dovecot (my LDA):

dovecot: lmtp(6271, steti at corpmail.monmouth.com): Error:  
KUIfNazkB05/GAAAJNuXoA: sieve: execution of script  
/var/mail/steti/.dovecot.sieve failed, but implicit keep was  
successful (user logfile /var/mail/steti/.dovecot.sieve.log may reveal  
additional details)

/var/mail/steti/.dovecot.sieve.log says:

error:  
msgid=<20110626220220.Horde.39S7NSTbl6BOB_Ssbo5BbpA at corpmail.monmouth.com>:  
failed to store into mailbox 'Create new folder [test]': Mailbox  
doesn't exist: Create new folder [test].

My server setup is as follows:

CentOS 5.6 x86_64
Apache 2.2.3 installed via yum from CentOS repo
PHP 5.3.3 installed via yum from CentOS repo
Horde 4.0.6 installed via Pear
Ingo 2.0.2 installed via Pear. Backend: sieve with timsieved (Dovecot  
Pigeonhole)
Net_Sieve 1.3.0 installed via Pear
Dovecot 2.0.13 installed from source
Dovecot Pigeonhole 0.2.3 installed from source

A few extra data points:

  - I have no trouble creating new folders via IMAP in Imp or from  
another IMAP client.
  - Pigeonhole is configured with "sieve_extensions = +notify  
+imapflags", the rest of the config is default.
  - I have debug logging enabled in my Ingo backend.  Most of the log  
looks fairly normal, but this entry stands out to me:

HORDE: HORDE [ingo] PHP ERROR: call_user_func_array() expects  
parameter 1 to be a valid callback, cannot access protected method  
Ingo_Transport_Timsieved::_debug() [pid 5865 on line 1205 of  
"/usr/share/pear/Net/Sieve.php"]

Has anyone seen a similar issue, or maybe have some insight into this problem?

Thanks,
Steve