[Owncloud] Calendar broken in 3.0.0?

[Hendrik Langer]

I have a fresh installation of ownCloud 3.0.0
However, the calendar does not show up. (It is enabled)

http://cloud.XXXXXXXX.XX/apps/calendar/index.php gives me a white page
and the following errors:

[Mon Jan 30 16:37:49 2012] [warn] [client 129.217.236.34] mod_fcgid:
stderr: PHP Warning:  require_once(calendar/calendar.php): failed to
open stream: No such file or directory
in /var/www/web192/html/h3ndrik/owncloud/lib/base.php on line 66
[Mon Jan 30 16:37:49 2012] [warn] [client 129.217.236.34] mod_fcgid:
stderr: PHP Fatal error:  require_once(): Failed opening required
'calendar/calendar.php' (include_path='/var/www/web192/html/h3ndrik/owncloud/lib:/var/www/web192/html/h3ndrik/owncloud/config:/var/www/web192/html/h3ndrik/owncloud/3rdparty:.:/home/php5/lib/php:/usr/share/php:/var/www/web192/html/h3ndrik/owncloud') in /var/www/web192/html/h3ndrik/owncloud/lib/base.php on line 66

Can anyone help me?
Thanks
Hendrik