I stumbled across the same error. No template was included in my installation of Roundup, which I did in a virtualenv with "pip install roundup". I manually copied the ./share/roundup/templates folder from the source archive into the roundup folder inside the virtualenv, and modified admin.py as follows:

In line 317, it reads:

    for N in 2, 4, 5, 6:

I modified this to read:

    for N in 1, 2, 4, 5, 6:

Now, the folder 'share' will be found, and I can choose from any template.