I need help with map upload!

I played minecraft with my friend and we decided that we need some plugins. I downoloaded map nad installed bukkit version and installed mods. I loggined in i can't find items in chest i tried to upload world and it says that file is too big. Tried to restore backup item still gone. In minecraft then i upload map items are in there, but i can't upload that map. Please help me.

So i can't upload my world? right????