Can't install linux-source-2.6.39 from backports?

[Ashton Fagg <ashton@fagg.id.au>]

Hi all,

Does anyone know why I can't install linux-source-2.6.39 from backports?

http://packages.debian.org/squeeze-backports/linux-source-2.6.39

But yet...

root@huygens:/usr/src# apt-get install linux-source-2.6.39
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package linux-source-2.6.39 is not available, but is referred to by
another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'linux-source-2.6.39' has no installation candidate
root@huygens:/usr/src#

I did this on another machine not too long ago and it worked fine.

Cheers,
Ashton