Make sure you enable the camera in the Pi if that's what you're using. It's simple to turn on. Use the "raspi-config" command, or if you're on the command line then try out:
sudo -s raspi-config
Next, you shouldn't need it, but just in case I'm listing it here for your review in the event you need to modprobe the sound driver for the onboard output on the Pi.
sudo modprobe snd_bcm2835
We also need to add a reference for a library in our .bashrc file to meet some of the dependencies of the software we installed above. This should run under the user that will be executing the Karen program. (You can also set this at runtime by prefixing it in the command call if you're not using a standard logged in user to start it up.)
echo "" >> ~/.bashrc echo "export LD_PRELOAD=/usr/lib/arm-linux-gnueabihf/libatomic.so.1" >> ~/.bashrc
Also, if you followed the general steps then you should have pulse audio installed now. You will want to make sure that it is started before continuing.