Hi Guys,
I am a developer working for Dan on some of the great plugins on offer, including wp-wiki.
I have been using wp-wiki with wordpress 2.8.4 for a project, I can vouch it does work in wordpress 2.8 but have noticed numerous plugin conflicts which I will address when I get sometime. If you need help with the plugin and getting it working, please send me an email,[dev[at]instinct.co.nz] and I will try my best to help you out as soon as possible.

your friendly wordpress geek,
Jeffry G