Maybe if you try giving a better explanation of what you want to achieve, I could help you. The Edison is running Linux. I can see from the error you have above ( File "/usr/lib/python2.7/site-packages/serial/serialutil.py") that this path is a Linux file system path.
You want to send data from a Python script running on your Edison to your Windows computer by one of the serial ports?
You will never be able to open a serial port on your Edison with this line ser = serial.Serial('COM8', 9600)
This is fine on Windows but not on Linux.