http://www.triplea-game.org
The best solution to the problem is to download TripleA. The above link will let you do exactly that. Not only will this engine allow you to play Larry Harris maps, it also allows you to play a good selection of player-created maps. Some of them are significantly better than any of Larry’s maps, at least to me. (Including New World Order, Rising Sun, and Domination 1914 No Man’s Land.)