Interesting, I hear alot of people on AP use it to do exactly that, A couple of thoughts.

1, Has it always done this? (If so, you may need to check your system requirements against what the program needs to run) Storage requiremets ok? and are all files the same format?
2, If it is only a new situation you find yourself in, maybe you could try calling Canon Aust, tech line, sit behind your machine when you call.

I used to use it with no problems, but have since switched to PS5.