gtk/g_object_compat_control error after upgrading Ubuntu

[Dave Kuhlman <dkuhlman cutter rexx com>]

I am running Kubuntu, which is the KDE version of Ubuntu, a debian based Linux. 
I upgraded (from breezy to dapper) using the standard Debian tools (apt-get). 
After doing so, I get the following error messages when I run gtk applications:

~ [1] gedit
gedit: symbol lookup error: /usr/lib/libgtk-x11-2.0.so.0: undefined symbol:
g_object_compat_control
~ [2] evince
evince: symbol lookup error: /usr/lib/libgtk-x11-2.0.so.0: undefined symbol:
g_object_compat_control

I've done Web searches and I have tried a number of things, but none of them 
fix this problem.

Is this the right list on which to ask this question?  It seems Gtk related.

Does anyone have a suggestion?

I've attached some notes on some of the things that I have tried, just in case 
they offer a clue.

Thanks for help.

Dave

Some additional notes follow:

=========================================================

When running gtk applications, for example gedit, I get the
following message::

    gedit: symbol lookup error: /usr/lib/libgtk-x11-2.0.so.0:
    undefined symbol: g_object_compat_control

This means, apparently, that every gtk application on my system is
broken.  Examples: gedit, firefox, realplay, epiphany, evince,
SciTE,

This symbol seems to be defined in libgobject-2.0.a.  I ran::

    $ nm -A --defined-only lib* | grep g_object_compat_control | less

and saw the following::

    libgobject-2.0.a:gobject.o:000036fe T g_object_compat_control

the "T" means "The symbol is in the text (code) section."


Then, to find out what package libgobject-2.0.a is in, I did the
following::

    $ dpkg -S libgobject-2.0.a

which displayed::

    libglib2.0-dev: /usr/lib/libgobject-2.0.a

So, I did::

    $ sudo apt-get --reinstall install libglib2.0-dev

But, for example, gedit still does not work.


Next, I did the following:

1. Retrieved a new, fresh /etc/apt/sources.list from
   http://www.ubuntuforums.org/showpost.php?p=1090438

2. Did another update/upgrade::

       $ sudo apt-get update
       $ sudo apt-get upgrade

But, gedit, for example, still produces the same error message.