Comment 1 for bug 13390

I can reproduce this same error on hoary

It's easy. I've a fat32 partition, and I don't repartition the hard drive - I
tell ubuntu to install in that fat32 partition.

The partition is formatted to ext3, but the "partition type" field continues
being "unidentified" by grub (0xc, a type of fat32 partition which grub doesn't
recognizes I guess). In the grub stage, grub tries to read the stage1 file from
the partition I'm goint to install ubuntu, ie: command(hd0,4)/boot/grub/stage1.

Because the "partition type" is set to something "unidentified" grub doesn't
knows how to read the ext3 partition, and hence fails to read the stage1 file,
and that gives that grub error and the install shows you a red screen. The fix
is to set the partition type to linux type (0x83)at the same time you format it
to ext3 or whatever.