Can't install gtkmm (package manager won't install libgtkmm-2.4-dev)

["Garth's KidStuff" <garthskidstuff gmail com>]

Hi All,

Help!  I'm trying to install a build environment on a machine I just
installed Ubuntu 8.04.1 on and the package manager won't install
libgtkmm-2.4-dev.  It gives the following message:

libgtkmm-2.4-dev:
 Depends: libatk1.0-dev but it is not going to be installed
 Depends: libcairomm-1.0-dev but it is not going to be installed
 Depends: libglibmm-2.4-dev but it is not going to be installed
 Depends: libgtk2.0-dev but it is not going to be installed

If I try to install some of the dependencies, I get this message:
libglib2.0-dev:
  Depends: libglib2.0-0 (=2.16.3-1ubuntu2) but 2.16.4-0ubuntu2 is to be
installed

This used to work -- I installed this build environment on a machine just a
couple of months ago and know I'm, not doing anything different.  Anyone
have any ideas?

Thanks tons in advance -- this is seriously killing my productivity!

-Garth