Thanks for your feedback. Unfortunately I'm too much of an OF newbie to understand what you mean with your second sentence.
But luckily, I got it to work in 0.8.4 by decreasing the dimensions in line 33 of example/src/ofApp.cpp:
vidGrabber.initGrabber(320, 240);
To keep up with that smaller size, also in example/src/main.cpp:
ofSetupOpenGL(320, 240, OF_WINDOW);