root@mythtv:/home/mythtv# dpkg -i linux-headers-2.6.21-2-486_2.6.21-6_i386.deb
(Reading database ... 76672 files and directories currently installed.)
Preparing to replace linux-headers-2.6.21-2-486 2.6.21-6 (using linux-headers-2.6.21-2-486_2.6.21-6_i386.deb) ...
Unpacking replacement linux-headers-2.6.21-2-486 ...
dpkg: dependency problems prevent configuration of linux-headers-2.6.21-2-486:
 linux-headers-2.6.21-2-486 depends on linux-headers-2.6.21-2 (= 2.6.21-6); however:
  Package linux-headers-2.6.21-2 is not installed.
 linux-headers-2.6.21-2-486 depends on linux-kbuild-2.6.21; however:
  Package linux-kbuild-2.6.21 is not configured yet.
dpkg: error processing linux-headers-2.6.21-2-486 (--install):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 linux-headers-2.6.21-2-486