Difficulties partitioning disk FreeBSD 9.0

[Bernard Higonnet]

I am trying to install 9.0 on a small notebook on which I have 
previously successfully installed 8.2.

I don't get very far. When defining partitions I have opted for Guided 
and chosen a drive with enough space (3.5GB), Entire disk. I am then 
asked if I'm sure I want to proceed, to which I answer "yes". I am then 
shown the results and invited to "Finish". I'm then warned I will lose 
all my data. I "commit" and get

Bootcode Error Device not configured
followed by
Error  Error installing partcode on partition ada0p1

at which point installation ends.


I have searched for these messages with no success...

TIA
Bernard Higonnet