Revised your code with pound signs for those that don't know code to get rid of the errors. I'm not seeing a label or anything popping up on the charts however. Have you used this code? I dropped it into a daily chart and left the length at 252 and got nothing. Maybe a shorter time period?
##IV code, implied vol
##
declare upper;
input period = AggregationPeriod.DAY ;
#hint period: time period to use for aggregating implied volatility.
input length =252 ;
#hint length: #bars to use in implied volatility calculation.
def ivGapHi = if isnan(imp_volatility(period=period)) then 99999999999 else imp_volatility(period=period);
def ivGapLo = if isnan(imp_volatility(period=period)) then -99999999999 else imp_volatility(period=period);
def periodHigh = highest( ivGapLo,length=length);
def periodLow = lowest( ivGapHi, length=length);
def ivRange = periodHigh - periodLow ;
def ivp = round( 100*(imp_volatility(period=period) - periodLow)/ivRange, 0);
AddLabel(1, Concat("IV%: ", ivp), color = CreateColor(255-(ivp*2.55),ivp*2.55,0));
