Ah, not xml then - nice find. This should fix it too then:

http://lists.horde.org/archives/cvs/Week-of-Mon-20080526/079006.html

I did and I found a workaround. In lib/Horde/Config.php on line 547, I 
changed md5(microtime()) to md5(rand()) and it seems to work now (I 
don't know if replacing the other occurrences of microtime() is 
necessary).



The server is a dual-core machine with thread support for PHP and 
Apache using mpm-worker. So, I'm wondering if it's possible that 
microtime() actually returns the same time more than once...

Definitely sounds like a problem with the DOM extension. Can you play 
around with doing basic xml parsing on the two installs?

The config/conf.xml is fine (fresh install, no previous version). I 
noticed a couple of other things:

- the same error occurs with Horde 3.1

- the error does not occur on another server with almost exactly the 
same setup: PHP 5.2.6 on Gentoo Linux, compiled against the same 
libxml, etc.



The only difference is that the server where it works is running 
mod_php and the server that produces the error is running php as fcgi. 
Could that be a lead? I raised the log-level, but no information is 
logged when I open the configuration. The weird thing is that all 
applications (IMP, Kronolith, etc.) work fine. That's also the reason 
why I only noticed it now when I prepared upgrading to the new stable 
release. I hadn't touched the running configuration in a long time...

Check if your config/conf.xml file is broken. And did you upgrade from 
an earlier version?

This is a fresh install, only the *.php.dist files were renamed to 
*.php. When I go to "Administration -> Configuration", only some of 
the tabs are shown and the options shown are often in the wrong place, 
that is, they should be in another tab (see attached screenshot).