Search not always working

[WhatBots]

Hello. I have the Revolution One (3.0) theme, running on Wordpress version 2.6.1

Sometimes the "Looking for something in particular?" search box does not find text that is on my website. I found a report that said WordPress had this problem. I'm guessing that the Revolution theme uses the underlying WordPress search. Is that the case?

If so, the answer would presumably be to upgrade to WordPress 2.8.4. I would have done this before asking but I want to delay the upgrade if possible, in case of problems with the upgrade. I'm not experienced in this area and would be glad of any comments.

Apologies if this has been answered before - I have looked, but there's too many irrelevant results returned. Everybody has a Search box, I'm searching for problems with the search box, so everybody's site gets returned.

The site is http://ccgi.ponds.force9.co.uk/whatbots/

Regards,
Brian (a different one)