[horde] Registry objects should never be cloned.

[J. W. Andersen]

I went through an ordeal trying to figure out which Horde version
would work with which PHP, and would finally try the latest, and,
presumably greatest, which brings me to PHP 5.1.2  and Horde
3.1-RC2. No luck there either. Apache is 2.0.55.

test.php run fine, with no lacks whatsoever, apart from FTP support,
LDAP support  and PostgreSQL support(which I do not use) and
mime_magic, where I use fileinfo instead.

When I try to access horde, it its awarded:

A fatal error has occurred

Registry objects should never be cloned.
No reports come up in apache logs or php.log. In horde.log I get:

HORDE [emergency] [horde] Registry objects should never be cloned. [on 
line 1120 of "/www/webmail/horde/lib/Horde/Registry.php"]

What am I doing wrong ? Any help highly appreciated.
/Joern.