Hi, may I know why the following code generates error? Thank you

Code
	vars underlyingPrices = series(price(0));
	vars underlyingRsi = RSI(underlyingPrices, 14);

	if(!NumOpenShort && !is(LOOKBACK) && (underlyingRsi(0) < 25) && ((price(0) - price(5))/price(5) <= -0.10)) { }


The error:
Error in 'line 26:
@underlyingRsi_02458(): syntax error

Thank you