Some additionnal notes:

I checked a machine which is under SL302-64 bits
(also a dual-opteron, but from an other constructor).
By chance, this machine is IDE, and so I encounted
no problem during installation.

I checked  the /lib/modules and found the previously
evil modules mpt*.o, and the second one called
mptscsih.o also failed to load due to unresolved
symbols. The other one used (mptbase.o) loads
without problems but cannot initialize because
it uses the previous one.

So the question is:
is it a compilation mistake if this module does
not work ? Or is it because x86_64 does not
support it ?

I'm trying to answer to the question by
rebuilding the src.rpm for the kernel with a
modified .config.

Help/clues would be appreaciated.

Regards,
--
Yannick Perret