Flex Error

TypeError: Error #1009: Cannot access a property or method of a null object reference.
    at mx.charts::AxisRenderer/calcStaggeredSpacing()[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\charts\AxisRenderer.as:2195]
    at mx.charts::AxisRenderer/calcRotationAndSpacing()[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\charts\AxisRenderer.as:1586]
    at mx.charts::AxisRenderer/adjustGutters()[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\charts\AxisRenderer.as:1326]
    at mx.charts::AxisRenderer/set gutters()[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\charts\AxisRenderer.as:798]
    at mx.charts.chartClasses::CartesianChart/updateAxisLayout()[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\charts\chartClasses\CartesianChart.as:2028]
    at mx.charts.chartClasses::CartesianChart/updateDisplayList()[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\charts\chartClasses\CartesianChart.as:1355]
    at mx.core::UIComponent/validateDisplayList()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as:6214]
    at mx.managers::LayoutManager/validateDisplayList()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:602]
    at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:675]
    at Function/http://adobe.com/AS3/2006/builtin::apply()


this error occurs when you have only 1 dataset and your dataset name is wider than the chart..

this is a bug of Flex and you can make a workaround for this. visit this http://bugs.adobe.com/jira/browse/FLEXDMV-1821