the current version doesn't work with 3.1
The WMT currently consist out of the following:
mapwrite.py - A library for reading and writing warzone 2.2 maps.
diorama.py - A random map generator for warzone 2.2 with a GUI.
makemap.py - A non-interactive random map generator for warzone 2.2.
The WMT have been written for Warzone 2.2, but trunk should also work. Currently trunk can't render roads very well at all, so you will get much better results when using Diorama with the 2.2 branch of Warzone.