I tried to install the Character Animator free trial but it appears that my camera is busy. I have no other programs running in background and I tried to switch the camera a lot of times. I also tried to deactivate my antivirus. I have a Logitech webcam.
I sometimes see this if I have been using other webcam products recently, like video conferencing or even video editing sometimes. I find usually restarting the computer seems to solve it - does that work for you? If not, most likely something else is trying to access it, but if you've already tried shutting down everything I'm not sure what else you can do. Some other threads that might help: