Could it be that I didn't properly add Vuforia to the project? The instructions aren't very clear and the instructions on the Vuforia website seem like way different. Since the SimpleIRWorld example doesn't build, I just used my project and added that code and those images from that, like so:
almost 10 years ago
I figured it out. My friend noticed that I had -Obj-C instead of -ObjC. I don't know if it was already like that or if I had put it in there like that. Nevertheless, then all I needed to do was add/link the IR Extension library (libExtensionVuforia.a) to my project.