I seemed to have nailed the problem repository. It's that new one I just added "planetccrm" yesterday and that's where it came from. Problem is, I don't see it listed on your sources.list file. The way you can figure it out is:
1) comment out all repositories except for freshrpm in /etc/apt/source.list
2) # apt-get update
3) # synaptic
3a. check version of pygtk2 that is "available"
4) uncomment one of the repositories that you commented out in step 1
5) repeat steps 2-4
When you find the repository where there is a new "pygnome" available, that one is the one causing problems.