[Plugin: Business Directory] Problems with editing listings

I’ve been using this plugin for a month or so with mostly good experience.
Upgraded to the latest version with “categories” just last week and managed to add a category to an existing listing, then I upgraded to WP 2.8.4 a few days ago (not sure if this is coincidental?)… now I can no longer do anything to existing listings without getting a message saying either “Listers description contains invalid characters, fix and re submit” or ” Listing is too long”.

The listings have already been approved and nothing is changing except the category, what could be going wrong?

https://www.ads-software.com/extend/plugins/business-directory/