I guess you can install another "linux-image-* " and get a matching "kernel-headers-* "
Google : 2.6.32.46+drm33.20
.. will show that the "drm33.20 changes" are included in other / later kernels.
Example ( Package "linux-headers-2.6.32-35" )
http://www.ubuntuupdates.org/package...ders-2.6.32-35
→ → Change Log →
* Linux 2.6.32.46+drm33.20
-- Herton Ronaldo Krzesinski Mon, 10 Oct 2011
.