ImportError: No module named serial
On my ubuntu 14.4 with python 2.7 as default, I installed pyserial for python3 (which my IDE is using actually) with the help of following command:
sudo apt-get install python3-serial
First use the two commands (which pip & which python) to get the exact path of the python and pip commands.After this only you will be able to determine the exact issue.
For me, the problem was solved by running the script importing serial in a user (not administrative) context. Windows, not Mac, so YMMV.