One more thing, do you also have pygobject and pycairo built, and perhaps libglade loaded? Looking around those seem to also be dependencies. That is of course in addition to the usual gtk-dev stuff which I am sure you already have loaded.
Pygtk was on the list of things I was going to build since there is an Mplayer front end that uses it I would like to try. Pygobject as well as pycairo if they are needed could go in the same extension as pygtk. I am able to sneak about an hour with TC now so I will try to help see what the issue is. I wil let you know if I see what is causing an error.