Why do I get error, Invalid command 'PythonHandler'?
Solution 1:
Have you enabled mod_python.load in mods-enabled? You can do this by just creating a softlink to the same file in mods-available.
Solution 2:
more easy way to do it
a2enmod python
Solution 3:
On Ubuntu, you need to:
apt-get install libapache2-mod-python