Tom, regarding:
File "../../../AUTISM_SCRIPTS/motionprogram.s", line 396
maxrdiff = max(abs(k) for k in motdiff[0:3])
^
SyntaxError: invalid syntax

That is my mistake for using new 2.4 syntax when backwards-compatible syntax would work just as well. It should be:
maxrdiff = max([abs(k) for k in motdiff[0:3]])
I'll update it on the server here when I get a chance to check it in and go through the re-release process, but you can make that edit yourself if you want. If you encounter other similar errors, they can probably be fixed the same way (by adding the square brackets just inside the function's parentheses). I didn't intend to use any 2.4-only features, so let me know what comes up.

As for Tkinter, I believe it's part of the standard OS X installation of Python, so hopefully just fixing the syntax error will allow it to run successfully on OS X. (I don't remember installing it with macports, and "port installed" does not list it as installed. When I run any Tkinter code directly on my mac, it comes up in some OS X-specific aqua application, *not* through X11. The menu bar reads "Python" as the application name, and it has the dock icon of the Python Launcher rocketship. The path to that application is
/System/Library/Frameworks/Python.framework/Versions/2.5/Resources/Python.app
And the "About" lists copyright to Apple. So I'm pretty sure Tkinter is default install on OS X at least 10.4.)

If you do want to try upgrading python on OS X, check this page:
[www.python.org]

The linux error is certainly because Tkinter is not installed. Unfortunately I don't know anything about installing software on Linux. Presumably there's some kind of package manager you have to use. If you have sysadmins, your best bet is to ask them to install it. If you're running linux yourself, then I guess you have to install it yourself. Sorry I can't help more with that part...

-dave