Exception when trying to open Chart Board view

I'm getting the following exception when I try to open chart board view for a selected version. Am I missing some library? The address pointed to:
http://.../secure/ChartBoard.jspa?decorator=none&selectedProjectId=10000&selectedBoardId=10310

Exception:
An error occurred whilst rendering this message. Please contact the administrators, and inform them of this bug. Details: ------- java.lang.NoSuchMethodError: org.jfree.data.xy.XYSeries.(Ljava/lang/String;)V at com.pyxis.burndown.JFreeChartBurndownRenderer.addCurve(JFreeChartBurndownRenderer.java:57) at com.pyxis.burndown.JFreeChartBurndownRenderer.render(JFreeChartBurndownRenderer.java:34) at com.pyxis.greenhopper.jira.actions.ChartBoardAction.getBurndownLocation(ChartBoardAction.java:41) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.velocity.runtime.parser.node.PropertyExecutor.execute(PropertyExecutor.java:111) at org.apache.velocity.util.introspection.

...and I'm running this with JIRA 3.8.1 and GreenHopper 1.2-jira37.

Hi,

Use the 1.2-jira39 instead.
I Think that may solve your problem.

Cheer,

Thanks! Now it seems to work.

Great I am glad you worked it out.

Cheers,