[horde] IMAP Error

[Stephan Cursiefen]

Hello everybody,

I installed horde the very day, including imp, but I can not login to it with 
authentication driver 'imap'.
Running the imap test from imp always gives me the same error message:
-------------------------------------------------------------------------------------
server="localhost" user="myself" 
mailbox="{localhost:143/imap/notls/novalidate-cert}INBOX."
bool(false)
-------------------------------------------------------------------------------------
It works fine with squirrelmail, eg, or with kmail and other clients, but not 
this way. Can anybody give a hint what to do? Thanks a lot. 

Stephan