I am using  Occidentalis OS and have installed OpenCV in it. I get the following message while importing cv2 in a Python program.
pi@raspberrypi~$ python cam.py
Traceback (most recent call last)
File "cam.py", line 1, in <module>
    import cv2
ImportError: No module named cv2
The  cv2.so file is stored in -  /usr/local/lib/python2.7/site-packages/.
Can someone please tell me why this message is popping up and how to solve this?