The following code produces an error message in the Processing IDE:
from pyfirmata import Arduino,util
"No module named pyfirmata"
I have no problem running the code directly in the python 2.7 interpreter.
But, I can't access the Processing API from the interpreter.
You'll have to place the library in question inside your sketch folder. Python Mode doesn't use your system python, and cannot see any of the modules installed there.
Can't access pyFirmata from Processing.py