I was doing fine until I got to section 9 - Install some software. I typed the long command line in and checked it several times, then pressed <Enter> and got the following message: Package linux-kernel-headers is a virtual package provided by: linux-libc-dev 2.6.20-16.29 You should explicitly select one to install. E: Package linux-kernel-headers has no installation candidate and was then returned to the prompt. First, is that critical to continuing through the list? And if so, could someone explain what to do in this situation, or point me to a place where I could find out?