Upgrade using a partition != hda1

[Leonardo Bentes <leo pangeia com br>]

Hello,

My RedHat 5.0 is installed into partition hda4. The other partitions are
NTFS (hda1), FAT (hda2) and swap (hda3).

When I tried upgrade to RH 6.1, using either graphical and textual
interfaces, I got the following error message:

Error mounting ext2 filesystem on hda1: Invalid argument

And then, the upgrade process stay froze at message:

Searching for Red Hat Linux Installations...

Does anybody knows how can I choose the right partition, in this case
hda4, to procced the upgrade?

Thanks in advance,

	Leonardo Bentes