[imp] can't create folders

[vikram at popgen.org]

My horde/imp installation is working well now, except for a few glitches here 
and there.  One of them is that I only have one folder: INBOX, and I cant seem 
to be able to make additional ones.  When I click on Folders, the server stops 
responding and the screen does not change.  

Redhat 8.0
Qmail 1.03
Courier-Imap (latest version)

Also, when i open address book, I get a particular error like this:

Notice: Undefined index: workphone 
in /var/www/html/mail/horde/turba/templates/browse/search.inc on line 14

I wish there was a comprehensive documentation available for imp 
configuration.  

Thank you guys for all your help.

Greetings,
Vikram