It is a long story but I have been trying to get a stable and repeatable way of building an Ubuntu Intrepid server for home use. To cut a long story short (I will fill in the gaps later), I ended up with the Sun VirtualBox vboxdrv not being complied into the kernel.
Lots of digging later and I have a solution;
I used the following commands (not sure if all are required)
sudo aptitude install kernel-package
sudo aptitude install linux-source
sudo aptitude install build-essential
I then tried
sudo aptitude install linux-headers-2.6.27-9-generic
without success so I did
and then (as it said it was the server kernel)
sudo aptitude install linux-headers-2.6.27-9-server
the final command to recompile the kernel is
sudo dpkg-reconfigure virtualbox-2.0
which finally gave me a working Kernel with vboxdrv installed and working. Phew!