I think the sys path is correct, cv.pyd and cv.pyd reside in c:\\OpenCV2.3\\build\\Python\\2.7\\Lib\\site-packages.
>>> import sys >>> sys.path
I had the same issue.This was an issue with OpenCV Engine.Download OpenCV engine from https://github.com/thumbor/opencv-engine/releases/tag/1.0.1 and save it as engine.py in \Python27\Lib\site-packages.use cv2.cv instead of cv2.cv as cv.