Thanks for the heads up - the vm-config needed some updates which have just been posted to github. If you initially pulled down the config via git, you should be able to just run the following commands to get things working:
> git pull
> vagrant destroy
> vagrant up
The destroy command will just remove any VM that was in the process of updating to make sure we avoid incompatibilities, but you shouldn't need to run the "vagrant box add" command again.