The documentation you are pointing to is quite outdated, which TurboGears version are you trying to use? Latest TG versions don't depend on repoze.who-friendlyform anymore. Try to delete your virtualenv, recreate it and then install TurboGears with pip install tg.devtools
.
You can find latest TG version documentation on http://turbogears.readthedocs.org/en/latest/#installing-turbogears with a tutorial on using ToscaWidgets at http://turbogears.readthedocs.org/en/latest/cookbook/TwForms.html
Also latest ToscaWidgets documentation has been moved at http://tw2core.readthedocs.org/en/latest/
If you want to experiment with TG2 and Forms there are also a bunch of runnables you can play with: http://runnable.com/TurboGears