I reduced your script to just the input portion and it ran fine under straight Python ( I have both Python 2.0 installed for development as well as the Python 1.5.x that's running under Poser). If you're still having trouble I'll try it again tonight under Poser. FYI, I have found that On My Machine (OMM) Poser does not like running a script that has a Tkinter gui AND brings up the Python console window under Poser. The console and the GUI tend to beat up on each other. If you're debugging, close the GUI first from task manager or the start bar and then the console should come back with the error message(s). Important safety tip would be not to write a script that has a gui and then tries to print to the console. For anyone doing any serious gui work I heartily suggest taking a look at Python MegaWidgets at: http://www.dscpl.com.au/pmw/ Has a bunch of python scripts that build up on the basic Tkinter-Python widgets to make things like ComboBoxes, validated entry fields, etc. Heck of a lot easier to use than writing it yourself. It's pure python so it should run on a Mac or PC. I have tested it on my PC and one of my unindicted co-conspirators successfully tested it on his Mac. PMW is heavily featured in the book "Python and Tkinter Programming" so it should be free of alien influences.