I had a chance to install in another 280R here at CPqD.
Although the configuration was almost the same, I decide
to try to see if the error would be exactly the same.
But, for my surprise, I had no error! So I got the disk
back on my own machine and saw the same error.
I started checking all components to find any difference
between the two system. They have the same processors
(2x UltraSparcIII 750 MHz), the same onboard FC-AL SCSI
controller (Qlogic ISP2200A), the same QuadFastEthernet
but different graphics boards. So I tried to install on
my own 280R without the graphics board and everything
worked flawlessly. Conclusion the problem was with the
PGX64 graphics board. I can't understand why though.
Maybe you can have an idea about what caused the error.
Anyway this story can be useful to others.