I tried originally to upgrade Redhat 6.0 using files in the
root partition to upgrade the same partition.  It failed
with a couldn't find RPM database error on the main screen.
I rebooted and tried rpm --rebuild after upgrading to the
Redhat 6.0 version of rpm.  This did not help.  Then I
noticed on the other screen the error regarding a mount on
/tmp/hdimage.  So I copied all the files to another
partition and got much further (till the problem I worked
around in bugid 2506.  Has anyone been able to use the same
partition to upgrade itself?

I only have a single root partition, no other partitions.

Another note:  bugid 2142 seems to mention this problem in
the last comment but I think their other primary issue was
resolved and so it was closed.