Thank you for showing me a cool mod. I like it.
The sad news are, from what I read in the last posts of the thread, the mod is not updated, at least not from its official author. But take a look to this comment: http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/1275106-1-5-2-forge-castle-defenders-v-1-2-big-update-new?comment=2198 He says that he's going to update the mod, and the comment is from June of this year.
Thank you! Do you know what version it is compatible with?