[horde] After Update to latest pear packages cannot use Horde Configuration

[Twilek]

Hi,

after having updated to the latest pear packages (horde-5.2.0 etc.)  
the Admin config page says that I need to update the horde config.  
When I try to load the config page  
https://www.xxx.com/horde/admin/config/config.php?app=horde I get this

1. Horde_ErrorHandler::catchFatalError()

Details

ErrorException Object
(
     [message:protected] => Call to undefined method  
Horde_Config::_configLDAPUser()
     [string:Exception:private] =>
     [code:protected] => 0
     [file:protected] => /usr/share/php/Horde/Config.php
     [line:protected] => 672
     [trace:Exception:private] => Array
         (
             [0] => Array
                 (
                     [function] => catchFatalError
                     [class] => Horde_ErrorHandler
                     [type] => ::
                     [args] => Array
                         (
                         )

                 )

         )

     [previous:Exception:private] =>
     [severity:protected] => 1
     [logged] => 1
)

I don´t use LDAP. Where does it fail? Horde itself seems to work  
without problems so far.

Regards

Henning