How can I enable "metrics" tab in phpUnderControl?

I downloaded the latest version of phpuc and ezc/Graph. I tested the example project for phpuc and whenever I view the metrics tab I keep getting a null pointer exception:

java.lang.NullPointerException
  at net.sourceforge.cruisecontrol.chart.PieChartData.produceDataset(PieChartData.java:52)
  at de.laures.cewolf.taglib.DataContainer.getDataset(DataContaine开发者_运维知识库r.java:53)
  ...
  ...

What did I do wrong?

I was pulling my hair out over this recently - one of the PHP graph classes has a bug which makes graph creation fail. The easiest way is just to rename it (assuming Ubuntu, the path may differ for you):

> cd /usr/share/php/phpUnderControl/Graph/Input/
> sudo mv ClassComplexityInput.php ClassComplexityInput.php.bak

More info at the bottom of http://recursive-design.com/blog/2011/05/13/continuous-integration-for-php-with-php-under-control/