I have a homemade cd which has already been used to upgrade another system
and to install a few other, so it has been tested and found ok.
The problem is that the installer gets a SIG7 right after loading raid5
module (it succeeds, so it is not a permission problem).
Also, the machine to be upgraded has been running RH6.0 for quite some time
without a hitch, so it's not a hardware problem, either.
Tried everything, from disabling cache memory to slowing the system down,
to no avail.
A signal 7 means the machine ran out of memory.