Chapter 7 - OpenCV error

[Troup]

I couldn't get Chapter 7 to work, so I downloaded the project here and got a similar error. re: "(-215)"
If useful, please look into for update. If not, and this is an error of my own, let me know and I'll close this. Not necessarily looking for someone to fix this for me - just relaying my user experience. Thanks! Unsigned int error, perhaps? I don't know much.

OpenCV Error: Assertion failed (mask.depth() == CV_8U && (mcn == 1 || mcn == cn)) in copyTo, file /Users/alexandershishkov/dev/opencv2.4.9/opencv/modules/core/src/copy.cpp, line 271
libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /Users/alexandershishkov/dev/opencv2.4.9/opencv/modules/core/src/copy.cpp:271: error: (-215) mask.depth() == CV_8U && (mcn == 1 || mcn == cn) in function copyTo