Roundcube dead since update

[Thomas Z.]

Hi,

I've installed Kolab 3.1 on a fresh CentOS 6.4.
Yesterday I made 
    yum update 
which yielded
   Updated: kolab-cli-0.6.8-13.8.el6.kolab_3.1.noarch
   Updated: pykolab-0.6.8-13.8.el6.kolab_3.1.noarch
   Updated: libkolabxml-1.0.1-6.4.el6.kolab_3.1.x86_64
   Updated: php-kolabformat-1.0.1-6.4.el6.kolab_3.1.x86_64
   Updated: roundcubemail-plugins-kolab-3.1.7-2.8.el6.kolab_3.1.noarch
   Updated: php-Smarty-3.1.13-4.3.el6.kolab_3.1.noarch
   Updated: kolab-webadmin-3.1.1-2.5.el6.kolab_3.1.noarch
   Updated: kolab-syncroton-2.2.3-4.8.el6.kolab_3.1.noarch
   Updated: chwala-0.1-7.el6.kolab_3.1.noarch
   Updated: libkolab-0.5.0-7.4.el6.kolab_3.1.x86_64
   Updated: kolab-server-0.6.8-13.8.el6.kolab_3.1.noarch
   Updated: postfix-kolab-0.6.8-13.8.el6.kolab_3.1.noarch
   Updated: kolab-saslauthd-0.6.8-13.8.el6.kolab_3.1.noarch

After that, Roundcubemail didn't answer any more.

In httpd.log I find 

[Thu Nov 14 07:08:33 2013] [error] [client 192.168.178.34] PHP Warning:  
require_once(Roundcube/bootstrap.php): failed to open stream: No such file or directory in /usr/share/kolab-syncroton/lib/init.php on line 42 
[Thu Nov 14 07:08:33 2013] [error] [client 192.168.178.34] PHP Fatal
error:  require_once(): Failed opening required 'Roundcube/bootstrap.php' 
(include_path='/usr/share/kolab-syncroton/lib:/usr/share/kolab-syncroton/lib/ext:.:/usr/share/pear:/usr/share/php')
in /usr/share/kolab-syncroton/lib/init.php on line 42 
[Wed Nov 13 21:28:21 2013] [error] [client 192.168.178.34] PHP Warning:  
require_once(Roundcube/bootstrap.php): failed to open stream: No such file or directory in /usr/share/roundcubemail/program/include/iniset.php
on line 58
[Wed Nov 13 21:28:21 2013] [error] [client 192.168.178.34] PHP Fatal
error:  require_once(): Failed opening required 'Roundcube/bootstrap.php' 
(include_path='/usr/share/roundcubemail/program/lib:.:/usr/share/pear:/usr/share/php')
in /usr/share/roundcubemail/program/include/iniset.php on line 58 

So some files seem to be missing, or - what seems more plausible to me - the init.php is wrong. Has anybody else experienced this? Does someone know a remedy? Otherwise I have to go back to a luckily made backup.

Thanks in advance,
Thomas