Thank you Keith but I've already tried all the procedure exactly has you described with no success at all.
Powering off, full charge, and display on, doesn't change anything.
The serial number is automatically detected without problem every time I mount the beo5 in the base.
But if I try to update the firmware I always get the 4 screen shots I've post you before.
But in fact all this is not very important for me... because the downloading config file procedure works fine and I can re-configure my beo5 without problems at all.
However I met another beo5 little bug that I've explained here, and I would want to know if this issue happens to your beo5 too, thanks.