I am not familiar with Pentax cameras and how old it is versus the kernel
that you are using. Unlike Windows where you insert a driver disk, Linux
provides drivers with the kernel. If the camera did not exist when the
kernel is written then it would not be detected. You could try a newer
kernel or upgrade to Ubuntu 9.1. There are no guarantees that this will work
though.

If the camera has been around for awhile, then this is not likely the case.
It could be that it is not common enough yet or it could be an oversight.
Sometimes waiting is necessary until things get caught up. Most Linux users
have experienced this with some kind of hardware. Fortunately with cameras
you can remove the card and put it in a card reader. That's what I do and my
cameras are supported well. It is faster for me than looking for the proper
cable