It is a WEU (world editor unlimited) add-in. In order to open that map you need to use WEU, and I am not sure if it has any compatibility with the latest version of WE. Your best bet is pretty much to make another install of wc3, then patch it to a version that's compatible with WEU and then run it, you will definitely be able to open it. But first try to see if WEU works with the latest release of wc3.