Hi pecus,
This is not really an answer to your problem but: have you tried installing and using the
searchindex manager plugin (see
http://wiki.splitbrain.org/wiki%3Aplugins). For some reason, automatic indexing does not work on either of my 2 dokuwiki's but the plugin works like a charm (note: read the comments when installing the plugin as it shows some strange behaviour the first time it runs).