Difference between Categories and Listing Categories


sorry if I sound stupid here but can anyone tell me the difference between Listing > categories and Listing > listing Categories.

Initially the Listings > categories had a category in it named uncategorised which I renamed to Motorcycle Hire and Rental Directory

Than I started making my categories but whatever I do I can’t get listings to work properly or at least that’s how it looks.

If you go to http://www.ridetheworld.org you will see a link to Motorcycle Rental Canada, please click on this.

Now you will see a link [View Listing] please click on this and you will see:

“Sorry, we can’t find the content you’re looking for at this URL. Please try selecting a menu item from above or to the side of this message to get where you’d like to go.”

Can anyone tell me what’s going on here please, it’s most probably me not setting things up properly but there aren’t any detailed setting up documentation as yet.