CPD throws a NullPointerException

[INFO] Cobertura Report generation was successful.
[INFO] jCompany Controle Executing
org.apache.maven.plugins:maven-surefire-plugin:[]
[INFO] jCompany Controle [class org.sonar.plugins.cpd.CpdMavenCollector]
executing
[INFO] jCompany Controle Collecting duplications...
[INFO] jCompany Controle File suffixes : java
[INFO] jCompany Controle Exclusions : {}
[INFO]
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[ERROR] BUILD ERROR
[INFO]
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[INFO] Can not execute Sonar

Embedded error: java.lang.NullPointerException
[INFO]
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[INFO] Trace
org.apache.maven.lifecycle.LifecycleExecutionException: Can not execute
Sonar
       at
org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:583)
       at
org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeStandaloneGoal(DefaultLifecycleExecutor.java:512)
       at
org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:482)
       at
org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:330)
       at
org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:227)
       at
org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:142)
       at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:336)
       at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:129)
       at org.apache.maven.cli.MavenCli.main(MavenCli.java:287)
       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:597)
       at
org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
       at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
       at
org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
       at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
Caused by: org.apache.maven.plugin.MojoExecutionException: Can not execute
Sonar
       at
org.sonar.mojo.bootstrap.Bootstraper.executeMojo(Bootstraper.java:79)
       at org.sonar.mojo.bootstrap.Bootstraper.start(Bootstraper.java:62)
       at org.sonar.mojo.bootstrap.SonarMojo.execute(SonarMojo.java:112)
       at
org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:451)
       at
org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:558)
       ... 16 more
Caused by: org.sonar.plugins.cpd.CpdExecutionException:
java.lang.NullPointerException
       at org.sonar.plugins.cpd.CpdExecutor.execute(CpdExecutor.java:83)
       at
org.sonar.plugins.cpd.CpdMavenCollector.collect(CpdMavenCollector.java:52)
       at
org.sonar.mojo.InternalMojo.executeCollectors(InternalMojo.java:248)
       at org.sonar.mojo.InternalMojo.execute(InternalMojo.java:148)
       at
org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:451)
       at
org.sonar.mojo.bootstrap.Bootstraper.executeMojo(Bootstraper.java:76)
       ... 20 more
Caused by: java.lang.NullPointerException
       at
org.sonar.mojo.ProjectContextImpl.getResourceKey(ProjectContextImpl.java:232)
       at
org.sonar.plugins.cpd.CpdAnalyser$ClassDuplicationData.cumulate(CpdAnalyser.java:95)
       at
org.sonar.plugins.cpd.CpdAnalyser.processClassMeasure(CpdAnalyser.java:76)
       at org.sonar.plugins.cpd.CpdAnalyser.analyse(CpdAnalyser.java:60)
       at org.sonar.plugins.cpd.CpdExecutor.execute(CpdExecutor.java:81)
       ... 25 more
[INFO]
------------------------------------------------------------------------
[INFO] Total time: 4 minutes 54 seconds
[INFO] Finished at: Fri Apr 24 13:41:57 BRT 2009
[INFO] Final Memory: 124M/762M
[INFO]
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