bar out of valid range

[trtrav]

I have an indicator that uses DrawArrowDown. It works fine most of the time but occasionally runs into an error:
DrawArrowDown: bar out of valid range 0 through -1 was 0.
If I close the chart and create a new chart it usually goes away.
Any ideas on how I could handle this?
I have put all the suggested:

if (CurrentBar < 1) return;

type checks but this doesn't seem to be the problem. The valid bar range from the error says 0 through -1 and I am always using 0 (current bar).

Thanks