The website doesn't validate, it could be a reason for the bad rendering from konqueror.
The website in general responds very slowly for me in Firefox. I've mentioned it here before, and it could be a javascript thing.
Anyway, I notice it's a pmwiki-based site. It's possible that it could stand an upgrade to its pmwiki engine? Looks like it's running on 2.1.11, but the current release of pmwiki is at 2.1.27 (with a 2.2.0-beta63 available as well).
Otherwise, the site isn't all that complex, and may not really even require a wiki, per se. Seems like a handful of static pages would work just fine...
---John