What do you mean "invalid copies"? Also, what computer platform are you using? Do the files download okay but then when you create a disk image they aren't right?
These EOS disk images are intended to be burned onto floppy disks. So if you don't have a computer with a floppy drive you are out of luck. Also, on a Mac, I believe you might need an OS9 machine, but I'm not 100% sure of that. Anyway, the trick is to burn the disk image directly to a floppy without opening it up in your computer. There might be instructions on how to do this on the Emu website support page.
No registration is required to download these OS files, they are free for any Emu Ultra sampler user to download as they wish. However, you do need the sampler hardware for the OS to be of any use.
Also, it's a long shot, but you might try contacting Emu to see if they'll send you a floppy with the OS on it. There might be a small charge for it, but it would probably be worth it.
Finally, it's worth noting the OS 4.7 is a beta. I seem to remember there being some bug type issues with version 4.7, which is why 4.61 is still up on the web site.