Etch won't install to /dev/hdax

[Rodolfo Medina <rodolfo.medina@gmail.com>]

Hi.

I've just bought 6 DVD's (sources and binaries) of Debian Etch Official, but
don't manage to install the GRUB boot loader to /dev/hda8, or to /dev/hda7, as
I want. It gives me error message. I've done it hundreds of times with Sarge,
with never problems: why does this happen now? I don't want the installation to
take place to the master boot record because I want to experiment the new
Debian version in another partition of my HD, but, as I said, this procedure
was always perfectly successful the other times.

Any explanation/remedy?
Thanks,
Rodolfo