[CS4 AS2] Local Shared Objects don't load info

Hi, I’ve just finished a puzzle game and i’m working on a level select screen, each level is an individual frame and after completing one i use this code (replacing the number with the number of the level that was completed):

if(savegame.data.levelnum > 1){	savegame.data.levelnum = 1;
	savegame.flush();
}

I’ve already loaded/created the shared object at the start with:

savegame=SharedObject.getLocal("Styxisdata");

and then on the level select screen I check to see if the level that’s been clicked is unlocked like this:

on (release) {
	if(savegame.data.levelnum >=1){
		gotoAndPlay(113);
	}
}

But for some reason when I go to the level select screen, all the levels are accesible, even if I haven’t completed them. It’s the same on other people’s computers, so I know it isn’t just that my PC still has a shared object from completing them when testing.

Does anyone have any ideas?