After following the same procedure as above for config.sml, run
make smlnj
followed by
make install
as root. Now you should be able to run sml in the base domtool2 directory and run CM.make "src/domtool.cm";. If you don't see any error messages, then the DomTool modules are loaded and you can start poking them. For instance, running open Main; should print information on the primary entry-points.