grub> kernel (hd1,4)/boot/gnumach.gz root=device:hd1s3 -s
[Multiboot-elf, ...]
grub> module (hd1,4)/hurd/ext2fs.static --multiboot-command-line=${kernel-command-line} --host-priv-port=${host-port} --device-master-port=${device-port} --exec-server-task=${exec-task} -T typed ${root} $(task-create) $(task-resume)
[Multiboot-module 0x1c4000, 0x2cfe6a bytes]
grub> module (hd1,4)/lib/ld.so.1 /hurd/exec $(exec-task=task-create)
[Multiboot-module 0x494000, 0x27afe bytes]
This all seems correct.
What kind of hardware do you have? I don't think it is a IRQ
conflict, since it happens so early. But you might want to check if
there are any shared IRQs (you can cehck the file /proc/interupts in
GNU/Linux). Then try to disable those devices (either by removing
them, or recompiling GNU Mach without them).