It won't let you SAVE? Why not? Do you get an error? Do you get a buzzer? You need to provide more information on what you're doing and what's happening. Stop panicking, think/speak coherently, and we will try to help you.
What is your game called?
Have you changed the title since you first created it?
Have you ever been able to save files?
Have you added more plugins since saving?
Have you created multiple games (even test projects) and created save files from them?
As I understand it, MV puts saves of ALL games in the same location (at least in web mode). I am not sure if it displays all of them when you go to load, or only the ones for the current game.
I suggest you remove the save game plugin and JUST use the default scripts, while trying to work the problem out. Once you get it sorted, then add the save plugin back.