I agree, this is a bizarre problem.
I'm not sure, but this (at least for me) seems likely to be a directory location or permissions based issue. I had unzipped the archive into a shared folder where all of my samples are kept, but the downloaded sample I had provided was in my home directory. When I copy the shared location file to the home directory, it starts loading properly again.
I'm going to play with this some more later and see if I can narrow it down to an exact reason, it may not be cabbage's fault... but if it is it's probably an extremely rare set of circumstances. I have no idea if other people's problems fall into the same category, or if that was just a similar red herring.