Cannot install docker

[Schymanski Stanislaus (SDSC)]

Dear all,
I am trying to install the latest docker engine following the
instructions for debian jessy here:
https://docs.docker.com/engine/installation/linux/ubuntu/#install-using-the-repository

However, when trying to add the repository: 
sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/debian \
   $(lsb_release -cs) \
   stable"
I get the following error message:

aptsources.distro.NoDistroTemplateException: Error: could not find a
distribution template for Progress Linux/cairon-backports

I suspect that 'Debian' is expected but 'Progress Linux' is found. What
is the best way around this? Thanks a lot!

Cheers
Stan