This cause the following error. What's wrong in this codes?
"Error 041: Wrong series usage!"

Code
function run() 
{
	BarPeriod = 1440;

	if(is(INITRUN))
	{
		History = ........;
		assetList(......, 0);
		
		asset("A");
		asset("B");
		asset("C");
	}

	if(dow() == 1)
	{
		asset("A");
		vars price = series(priceClose());
	}
	else if(dow() == 2)
	{
		asset("B");
		vars price = series(priceClose());
	}
	else if(dow() == 3)
	{
		asset("C");
		vars price = series(priceClose());
	}
	else if(dow() == 4)
	{
		asset("A");
		vars price1 = series(priceClose());

		asset("B");
		vars price2 = series(priceClose());

		asset("C");
		vars price3 = series(priceClose());
	}
}