What you've done by following those directions is created an entirely new Python installation, separate from the system Python that is managed by Ubuntu packages.
Modules you had installed in the system Python (e.g. installed via packages, or by manual installation using the system Python to run the setup process) will not be available, since your /usr/local
-based python
is configured to look in its own module directories, not the system Python's.
You can re-add missing modules now by building them and installing them using your new /usr/local
-based Python.