The installation of dokuwiki requires some action difficult to perform in shared hosting environments for which no root access are available.
In particular, in page
http://wiki.splitbrain.org/wiki:install
chgrp nogroup dokuwiki/conf/users.auth.php
chgrp nogroup dokuwiki/conf/acl.auth.php
...
chown -R nobody dokuwiki/data
Some people solve this problem by using chmod 777 (see same page, bottom part).
Is there any more safe solution? And also, more notes should be written in the install page, because many people encounter this problem. (Search for the word 'Sergio' in the install page, I've made a note a while ago).
Thanks, Sergio