Hey Tim,
I've done some local testing, and if you're loading category records on a detail page it shouldn't make any difference, the permalink URL's should load the correct record.
The most likely issue is that either List Page URL or Detail Page URL are pointing to pages that don't exist. You can change these by going to Section Editors -> [Section you want to edit] -> Click on the edit link -> Click on the Viewers URL Tab
Cheers,
Greg
Greg Thomas
PHP Programmer - interactivetools.com