Version 1.21 fixes several bugs, including one important one when there is custom player data, and several more esoteric ones for when there is no custom player data, but is a custom player map. It also makes the map more robust, so that a map error does not prevent the map from being viewed. See the thread for full details.
Cross-Platform Civ3 Editor 1.30
A custom Civ3 scenario editor that expands on the possibilities of the original