I tried to upgrade RH 6.0 to 6.1, but it fails during 'analyzing installed system' with anaconda&python messages saying, that it can't mount /dev/hda8 because of '... bad parameters' or something like this. After this, installations exited. It is true, partition /dev/hda8 on my system contains no file system and have never been mounted normaly, because it contains raw data chunk used by Informix database server. I worked arround the problem by 'mkfs ' un that partition (destroying database, of course). However, it is not commonly acceptable solution :-(
*** This bug has been marked as a duplicate of 5618 ***