Well, you can always double check the file paths, but sometimes they'll still show up green even if it is correct. Here's one thing I do to fix it if that is the situation: Rename the icons to something that already exists in game (war3viewer can get you file names and paths real easy), then use the already-existing icons' file path, so it overwrites the pre-existing icon while in-game. Never failed for me that way.
-VGsatomi