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:~$ sudo apt-get install linux-headers-$(uname -r)
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  linux-headers-2.6.22-14-386
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 579kB of archives.
After unpacking 6574kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com gutsy-updates/main linux-headers-2.6.22-14-386 2.6.22-14.52 [579kB]
Fetched 579kB in 4s (134kB/s)                       
Selecting previously deselected package linux-headers-2.6.22-14-386.
(Reading database ... 104727 files and directories currently installed.)
Unpacking linux-headers-2.6.22-14-386 (from .../linux-headers-2.6.22-14-386_2.6.22-14.52_i386.deb) ...
Setting up linux-headers-2.6.22-14-386 (2.6.22-14.52)