Current head throws NPE when generating reports

The current head of this plugin does not generate the reports but throws NPEs:

java.lang.NullPointerException
at org.codehaus.plexus.i18n.DefaultI18N.getBundle(DefaultI18N.java:141)
at org.codehaus.plexus.i18n.DefaultI18N.getString(DefaultI18N.java:206)
at org.apache.maven.report.projectinfo.LicenseReport.getName(LicenseReport.java:75)
at org.apache.maven.plugins.site.ReportDocumentRenderer.renderDocument(ReportDocumentRenderer.java:122)
at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.renderModule(DefaultSiteRenderer.java:260)
at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.render(DefaultSiteRenderer.java:116)
at org.apache.maven.plugins.site.SiteMojo.renderLocale(SiteMojo.java:127)
at org.apache.maven.plugins.site.SiteMojo.execute(SiteMojo.java:95)
at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:418)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:534)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:475)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:454)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:306)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:273)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:140)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:327)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:120)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:269)
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.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)