Basic OpenCV Example Problem

Hey all!

Have small problem, just try to copy and paste the example from docs.derivative.ca/OpenCV to the script CHOP and get the error:

File "/project1/script3_callbacks", line 64, in onCook cv2.error: G:\devel\opencv\modules\imgproc\src\featureselect.cpp:365: error: (-215) qualityLevel > 0 && minDistance >= 0 && maxCorners >= 0 in function cv::goodFeaturesToTrack

Any ideas?