I am experiencing this too, unfortunately the machine is down so I can't
provide more info right now.

Basically what happens is that grub is trying to install itself on a
device that does not exist: /dev/sda, while the config et all is
pointing to /dev/hda (in my case).

I'll get back with more info.

''`. Gay scientists discover the Christian gene
: :' :
`. `'
`- Proudly running (unstable) Debian GNU/Linux