Wiki Page Numbers

We have installed the wiki plugin and posted some items. When we go to click on the 'Next page' link in a Wiki category it comes up with a 404 error. We have reset permalinks and re-installed .htaccess with no luck.

Here is a link:
http://medipeak.com/wiki/categories/lab-test-results/

Try the next page link at the end of the page. Thanks!