To actually run the application, you will need to provide the appropriate libTCOD DLLs or SOs for your system -- they must be in the directory you launch npc.py from (usually, right here where npc.py is).
These instructions are correct for libTCOD v1.5.1:
On Windows, you will want libtcod-mingw.dll, SDL.dll, and zlib1.dll. Alternately, you may use libtcod-VS.dll in place of the mingw version -- either should work just as well.
On Linux, you will want libtcod.so and possibly SDLlib.so (however, the latter
should be provided by your package manager if at all possible -- on
Debian/Ubuntu, try sudo apt-get install libsdl1.2debian).