This may happen because you don't have a patch or an update for Battlefront. Your map is now ready to play but sometimes it makes the game crash. When done extracting (if required), copy that file and then you paste that file in the AddOns folder (or just simply extract the file directly onto the AddOn folder). This should open an extraction wizard that lead you through the process of extracting the file.
To extract it, right click, and click Extract. Note that some mod files require extraction first and can be told by a zipper across the file icon. When done downloading, click My Documents, go to Downloads and find the file you just downloaded. Latest mods Luke ROTJ Jedi Robes Mod Star Wars Battlefront III Legacy Mass Effect: Unification Jakku: Graveyard of Giants Clone Wars Era Mod Space Kamino. When you find what you want, a download link. When you get there you will find SWBFI and SWBFII on the bottom left corner then click on Maps and it shows all of the mod map. After you finish go to your Internet browser and and go to Google than you search 'or any other mod website. If you already have one, ignore this step).
When you go there you need to create a folder called AddOn (or Addon. After that double click the LucasArts folder and go to Game Data folder and click that also. First you go to your computer then you click Programs Files than find LucasArts folder. Here's how to add your favorite mod maps for SW:BFI or SW:BFII. You can help Star Wars Battlefront Wiki by expanding it.