Very impressed with SilverStripe. It seems to be just what I wanted.
I just downloaded SilverStripe-V2.4.0.tar.gz, installed it and messed about with it for a while and it looks fine.
Then I downloaded a few modules that I wanted, unpacked them and went to update the database (dev/build), and there is no dev directory in the installation. It's not in the tar file either. Is it missing, or am I missing something?