'form_example.pyhp' defines form action as
action="/form_example.pyhp?form=get"
If example is located in a subfolder, this action will address a wrong folder.
Fix:
action="form_example.pyhp?form=get"
Diff is
4c4
< <form action="/form_example.pyhp?form=get" method="POST">
---
> <form action="form_example.pyhp?form=get" method="POST">
Fixed example is in attachment (just in case)
Fixed example