I too have this error. To shed a little more light (w/o fixing it though). I can copy the installer to an older Mac, it launches and installs OK. If I then copy the installed directories over that it created, I got it to work.

Otherwise, trying to launch the installer on this Mac complained about 33% into the progress bar that the Zip archive was corrupt. I'm suprised that it would use Zip compression on a Mac but just in case I tried Stuffit to open generic Zip files which it did OK. Then I tried reloading the MRJ component again from Apple. Still no luck.

I was going to boot with minimal extensions enabled but I've spent more than enough time already on this issue (for now anyway, since it basically works now).

Good luck!