[horde] horde 5.2.0 Fatal error: Fatal error: Call to undefined method Horde_Config::_configLDAPuser when entering horde config

[Tom Bühlmann]

Hello all!
Just updated all packages to pear.
Now i can't enter the horde config menu anymore.
I get this error:
Fatal error: Call to undefined method Horde_Config::_configLDAPUser() in 
/usr/share/php5/PEAR/Horde/Config.php on line 6724.

I cant update any other app. I only get a red sing telling me "invalid 
application". (in german: "ungültige anwendung")
Did i miss an important step in upgrading from horde 5.1?
Thanks for helping!

--Tom