When attempting an export of a template using 1.8.4rc4 I receive a file not found error in my browser. Closer inspection of my apache error log reveals the following:

[Fri Dec 31 15:17:53 2010] [error] [client 192.168.79.1] PHP Fatal error: require_once(): Failed opening required 'include/classes/class.domdocument.php' (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/1.8.4rc4/include/config.inc.php on line 70, referer: http://192.168.79.174/1.8.4rc4/hosts.php?sid=c8953f8dcba90aea

There is no class.document.php file in the include/classes directory, and none in the original tarball.