Problem with Kronolith from Horde.org

[Alexander Schröter]

Hi

I installed horde from the horde.org homepage ... step by step its 
working so far but with kronolith (latest stable release)I get an error:

Mar 25 11:11:19 HORDE [error] [horde] Unable to modify user's 
objectClass for preferences: [17] Undefined attribute type [pid 17758 on 
line 496 of "/usr/local/horde3/lib/Horde/Prefs/ldap.php"]
Mar 25 11:11:19 HORDE [error] [kronolith] Unable to modify user's 
objectClass for preferences: [17] Undefined attribute type [pid 17754 on 
line 496 of "/usr/local/horde3/lib/Horde/Prefs/ldap.php"]

Can anybody help me?

Regards Alexander