try using the live boot disc to reinstall grub after the freeze, otherwise my only question is, are you being impatient?? not letting it chug through to the end, ive found sometimes things can freeze up and eventually go right after a little time with some things so make sure its a bug and not that its thinking really hard

the other thing you could try is updating the installer before install to see if it provides a fix for your problem.
as to the 32bit 64bit there is no problems running 64bit linux on your machine, something with the install of Grub(or installer issues) is going wrong.