I implemented this as a local Kronolith preference, because 1) you 
might want to search different address books for fb urls and email 
addresses, and 2) imp's default address book preference is far 
complexer and not suitable for a shared one.

Bounty added: http://www.horde.org/bounties/details.php#kronolith_addressbook

We should add a "default address book" preference to Kronolith like we 
have in IMP. Or even make it a global preference.

It seems, that if in /horde/turba/config/sources.php the local 
adressbook is not the first in the array, and/or if the FreeBusyURL is 
incorrectly set, then the 'hang' can be reproduced. You probably have 
only one Address source defined (with correct or empty FreeBusyURLs 
set).



Using the default configuration of /horde/turba/config/sources.php the 
first address lookup is Netscape or Bigfoot or Verisign or so.



Now look at this function in /horde/kronolith/lib/Kronolith.php:

     function getFreeBusyUrl($email)

     {

         global $registry;



         /* Get the list of address books through the API. */

         $source_list = $registry->call('contacts/sources');

         if (is_a($source_list, 'PEAR_Error')) {

             return false;

         }



         /* Try retrieving by e-mail only first. */

         $result = $registry->call('contacts/getField', array($email, 
'freebusyUrl', array_keys($source_list)));

         if (is_a($result, 'PEAR_Error')) {

             return false;

         }

         return $result;

     }



The systems seems to hang or timeout after the "/* Try retrieving by 
e-mail only first. */" comment.



My workaround: I removed all but the local address book in 
/horde/turba/config/sources.php

and it seems to work fine like this, although I obviously have no 
Free/Busy information while assigning people to an event.

I cannot reproduce this. Furthermore, anything involving apache 
crashes is way beyond a Horde but and is likely a problem with your 
PHP/Apache install.

When trying to edit an event (not creating a new one!) in Kronolith 
then clicking on "Edit Attendees" stops (crashes) Apache/PHP and the 
httpd process has to be restarted.



Creating a new event works fine, but any urther change to the list of 
attendees is impossible.