Newbie boot problem

[Godric <godric@dial.pipex.com>]

Hi. I made the Hurd partition OK (I assume) which is hda4; made
Hurd fs on this OK (no errors reported). Got latest tarball
(19991025 from alpha.../gnu/marcus etc). Extracted OK to /gnu.
Made grub floppy OK (done it twice just to make sure) but when I
boot using (hd0,3) for grub name, at kernel=/boot/gnumach
root=hd0s4 -s I get the error *file not found*. I rechecked I got
the Hurd name for partition right (??). Tried a few other Hurd
names out of desperation but got some message.
I'm probably doing or done something stupid - any help or
suggestions much appreciated.