actionscript-3 - Null reference error in axis renderer when redrawing Flex chart Axis

Question

I have an application in which chart properties can be updated on the fly. I am updating my axis renderers for redrawing axis(There are some custom AxisRenderers which is extended AxisRenderer class in SDK). Some times it is throwing a null object error while changing the axis renderers. In Adobe forums it is asked, but no one suggested a workaround nor solution. I just wanted to know only from where the error stack is starting, From the debugger i found the error is in the line if (_bGuttersAdjusted == true && chart.chartState != ChartState.PREPARING_TO_HIDE_DATA && chart.chartState != ChartState.HIDING_DATA) of AxisRenderer.as. Do anyone have a solution? Thanks in advance