[imp] IMP not rendering & imapchildrensupport()

[Channing]

I'm getting the following error in my php.err

[12-Oct-2005 09:13:54] PHP Fatal error:  Call to undefined function:    
imapchildrensupport() in /var/www/html/horde/imp/lib/IMAP/Tree.php on  
line 81

I?m current on IMP & Horde with the exception of the file: 
imp/lib/IMAP/Tree.php as the aforementioned error keeps Horde and IMP 
screens from rendering.  (Horde's page has the INBOX frame as one of 
it's views.)  Here is the nitty gritty:

Horde (horde) 3.1-cvs Mail (imp) H3 (4.1-cvs)

httpd 2.0.52 (Apache)
php 4.3.9
dovecot 0.99.11
RedHat Ent. 4.1


On a side note, I'd like to thank the developers for such a great 
product and all their hard work!

Channing