_tkinter problem

I have the "tkinter" problem and need some assistance to straighten it out.

From the web page "http://wiki.python.org/moin/TkInter" I tested as in "step

1" and cannot import "_tkinter." I do not have that file on my computer, but do have tkinter.py in /usr/local/lib/python2.6/lib-tk. as well as the directories /usr/lib/tk8.5 and /usr/lib/tcl8.5.
This matplotlib and python stuff is great, but the documentation frequently feels like it is just a bit out of my grasp. I realize that all of this is free but I understand the instructions on the web page to repair only to the point of confusion. I'm not an expert. How do I modify my python configuration? Is there a file that needs to be edited? Which setup.py file do I use? Make? or python setup.py build and python setup.py install?
Thanks. I appreciate your help.
Paul Simon