libc6-dev dependency problem

["A.E.Lawrence" <A.E.Lawrence@lboro.ac.uk>]

I have just started with with debian-pure 64, and I seem to have hit a 
dependency problem similar to that which Eric Norman reported in 
http://lists.debian.org/debian-amd64/2005/02/msg00656.html.

First, my sources list has
deb (mirror)/alioth/debian-pure64 sarge contrib main non-free

Any attempt to install libc6-dev (and various other development 
packages) gives this problem:-

-----------------------------------------------------------------------
# apt-get install libc6-dev=2.3.2.ds1-20
Reading Package Lists... Done
Building Dependency Tree... Done
libc6-dev is already the newest version.
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
  libc6-dev: Depends: libc6 (= 2.3.2.ds1-20) but
2.3.2.ds1-20.0.0.1.pure64 is to be installed
Depends: linux-kernel-headers but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or 
specify a solution).
----------------------------------------------------------------------

I have tried several strategies including forcing the install with dpkg,
but that leads on to further problems. Various virtual packages like 
glibc-2.3.2.ds1-20 are reported as broken by aptitude.

As I am rather new to debian, can anyone throw any light on this? I 
suspect that I have made some elementary mistake. But I am worried in 
that the rproblems reported by Eric didn't seem to have a clear solution.

Adrian Lawrence