Warcraft map hosting problem

[starhanabi]

I have a map, Naruto Battle Siege v2.13, and the file size is 4mb+. I loaded the game in single player in warcraft and the map loads fine and i am able to play it with no problems at all. However, when i wanted to play it with my friends using the LAN option, an in-game error is displayed saying, "The map file is too big." or somthing like that... I heard people say if your map doesn't go beyond 8mb in size its alright. But in my case, the map is half of 8mb, wtf!!! Can anyone help me with this???