Clicking on the listing link results in error message

The website is a wordpress/buddypress installation. Everytime I click any of the categories in the listing or if I directly click the title of the listing that I posted, it would give me an error message - Page Not Found.

The website is
You would have to log-in to access the protected content.
Login: (username) sample-user / (password) sampleuser

Then go to
Click on either Cote d'Ivoire or United States link and it will return an error message.

I tried deactivating all the plugins and activating just the classifieds plugin but it still results in an error message.

Help pls!