todd@todd-desktop:~$ sudo apt-get install linux-headers-2.6.22.14.21
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Couldn't find package linux-headers-2.6.22.14.21
todd@todd-desktop:~$ sudo apt-get install linux-headers
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package linux-headers is a virtual package provided by:
  linux-headers-2.6.22-14-xen 2.6.22-14.52
  linux-headers-2.6.22-14-virtual 2.6.22-14.52
  linux-headers-2.6.22-14-ume 2.6.22-14.52
  linux-headers-2.6.22-14-server 2.6.22-14.52
  linux-headers-2.6.22-14-rt 2.6.22-14.52
  linux-headers-2.6.22-14-generic 2.6.22-14.52
  linux-headers-2.6.22-14-386 2.6.22-14.52
  linux-headers-2.6.22-14 2.6.22-14.52
You should explicitly select one to install.
E: Package linux-headers has no installation candidate
todd@todd-desktop:~$