I am trying to copy some hosts to my Zabbix 1.8 test environment. When importing the file I get an empty page (just headers) and the following error pops up in the Apache error log:

[Tue Dec 08 15:00:37 2009] [error] [client xxx.xxx.xxx.xxx] PHP Warning: require_once(include/classes/class.domdocument.php) [<a href='function.require-once'>function.require-once</a>]: failed to open stream: No such file or directory in /data/zabbix/web/include/config.inc.php on line 74, referer: http://blabla/import.php?sid=75b05f75f6e21bb5

The classfile class.domdocument.php is not present.