WEU is out of date. It wont work corectely in any way. Even if you got to work (i did) it mostly make the game crash when you play the map or it just say errors when you save the map and lots of problem. Uninstaling it is the best thing to do.. One of the only usefull thing that still work is the tile set thing (you can change then and even put up to 16 tile sets) in the "Edit Map".
TIPS: Do not use WEU for anything but the tile set and the feature about images (fade filtrer, preview screen, ect..) and DO NOT check anything on the right of the "Main Settings" of the "Edit Map" window or your map will get errors.