title: "ImportError: No module named tkinter" when using Pmw
body: <p>Here's my problem: I'm running the code in <a href="http://code.activestate.com/recipes/271249-how-to-create-linked-optionmenus-or-other-lists-in/">this</a> example.  I have Python 2.7 and 3 installed on my RaspberryPi but I have checked and double-checked, and I am running the code in 2.7.  I've installed Pmw 2.0.0 under 2.7, not 3, but when I try to run, I get the "ImportError: No module named tkinter" error.  I use Tkinter all the time, so it usually works fine, and I've done a search to verify that I'm definitely calling "Tkinter", not "tkinter", so I think it has to be a problem with Pmw, which also seems to be indicated by the traceback (posted in full at the bottom of my question).  I can't for the life of me find a specific place where Pmw is looking for lower-case "tkinter", and I'm at a loss for how to work around this.  I'm not eager to switch platforms--this is for work, so unless this is unfixable, I need to stick with Tkinter.  Oh, and I am pretty new to Python, so I would love to find out that it's a simple problem that someone on here can spot easily.</p>
  
  <p>import sys; print sys.path gives me:</p>
  
  <pre><code>['/home/pi/Desktop', '/home/pi', '/usr/bin', '/usr/local/lib/python2.7/dist-packages/distribute-0.6.28-py2.7.egg', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/pymodules/python2.7']
  </code></pre>
  
  <p>The full traceback is:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/pi/Desktop/LinkedMenusSample.py", line 151, in &lt;module&gt;
      Pmw.initialise(root)
    File "/usr/local/lib/python2.7/dist-packages/Pmw/Pmw_2_0_0/lib/PmwLoader.py", line 131, in __getattr__
      self._initialise()
    File "/usr/local/lib/python2.7/dist-packages/Pmw/Pmw_2_0_0/lib/PmwLoader.py", line 89, in _initialise
      raise ImportError(msg)
  ImportError: No module named tkinter
  </code></pre>