There's no difference whatsoever between Geneva and any of the other installers. They are *exactly* the same code, just they install a different scenery so, there's no reason why one would be more "difficult" than the others.
There's no reason to backup the installer, because by the time you might need it again, it might have be outdated and, since it's always freely available for download here, we are happily offer you our bandwidth to save you from the burden of having to backup the installer. The only thing that you need to store safely (although there IS a backup procedure for that, of course), it's your Serial Number.
Of course, if you say the checksum for the installer was "invalid", since the file we have online is obviously correct (and there's a way to verify this too, by checking the digital signature), it looks like all your issues were caused by a faulty antivirus, which corrupted the installer trying to "heal" it, because it mistakenly detected it as a threat.
So yes, I agree that in presence of a defective antivirus that catched a false positive, the installation with a corrupted installer might be basically impossible, but that doesn't mean that Geneva has any specific issues, it's just that for some reason that installer went corrupted.
