Access Violation? I'm not seeing why.

[SteveCRM]

char FileName[100];
		char ShortFileName[100];
		char todo[200];
		GetWindowText(ghWnd_File, FileName, 100);
		if(GetShortPathName(FileName, ShortFileName, 100) !=0) {
			strcat(todo, "open ");
			strcat(todo,  ShortFileName);
			strcat(todo, " type mpegvideo Alias mpeg");
			mciSendString (todo, 0, 0, 0);
		}

this gives me an access violation why!