[horde] Using Horde from a custom website --> Cannot redeclare _pear_call_destructors()

[roman stachura]

  Hi

I like to use the kronolith Application inside my website.

As described here: 
http://wiki.horde.org/Doc/Dev/LegacyApps?referrer=Doc/Dev/Registry#
Things work well. --> 
http://www.stadttheater-olten.ch/groupware/kronolith.php

But as soon as I integrate in my own code:
*Fatal error*: Cannot redeclare _pear_call_destructors() (previously 
declared in PEAR.php:773) in *PEAR.php* on line *777*.

The first  $registry->call('calendar/listCalendars'); leads to: Cannot 
redeclare _pear_call_destructors().

So how do I tackle this one?

regards roman