What you can do is simply click on your PC36IMG.ZIP file (assuming you have had it for a few days) on a windows computer and see if it opens so you can see it's contents. If it does that means more than likely the file has become corrupt SINCE YOU DOWNLOADED IT and that anyone downloading it now will have a corrupt file as I seem to have.
I'm going to try downloading it on another computer and see if that works.
Edit: It still says "invalid file" on the other computer.
I'll get back to you. I'm on vacation, so my EVO is my only source of internet, and the download will take quite a while.
Sent from my HTC EVO 4G using Tapatalk Pro.