TCL_LIBRARY and TK_LIBRARY env vars are set when I start up PyCmd from a cmd.exe window that does not have them set. this later causes matplotlib to barf. sure, I could set them or unset them in init.py, but they shouldn't be set in the first place, and especially they shouldn't end up pointing to the PyCmd install directory. frankly I just got lucky figuring out that was the problem because the message from matplotlib made me think I needed a separate tcl install, which I don't.
the only place I could find the string "TK_LIBRARY" is in the file _cx_Freezeinit.pyc in the library.zip file.
I'm running PyCmd-20120927-w64.zip from the snapshots on windows 7/64.