I installed RabbtVCS on Ubuntu GNOME 14.04 Trusty Tahr from the Ubuntu repositories (rabbitvcs-nautilus) and it did not integrate into Nautilus. It also seemed to cause other strange effects (mouse wheel not working any more, …?).

Installing the latest version from the RabbitVCS PPA fixed all this:

sudo add-apt-repository ppa:rabbitvcs/ppa
sudo apt-get update
sudo apt-get install rabbitvcs-nautilus3

Hope this saves somebody half an hour figuring out how to solve this 😉