It could be possible that the catalog you are using isn't working properly.
Please follow the below steps and see if this helps.
> Create a new catalog
> Import few images
> Create a collection using the images
> Try to export the collection as a catalog.
Let me know if this helps.
I've resolved the issue myself using KCPM Utility Pro. It is a utility that can repair/reset disk permissions in El Capitan. My permissions on my boot volume must have gotten messed up between moving files to and from the boot volume to accommodate a fresh install of El Capitan.
I've also come across this post on MacTouch:
Rather than the KCPM utility listed above, it recommends using the terminal to repair disk permissions using the following command:
sudo /usr/libexec/repair_packages --repair --standard-pkgs --volume /.
The article further goes on to discourge readers from downloading arbitrary compiled binary applications from the Internet and running them from Terminal.