NullPointerException when collecting the taglist report on Velocity project

[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Can not execute Sonar

[INFO] ------------------------------------------------------------------------
[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.codehaus.mojo.sonar.Bootstraper.executeMojo(Bootstraper.java:87)
	at org.codehaus.mojo.sonar.Bootstraper.start(Bootstraper.java:65)
	at org.codehaus.mojo.sonar.SonarMojo.execute(SonarMojo.java:117)
	at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:451)
	at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:558)
	... 16 more
Caused by: java.lang.NullPointerException
	at org.sonar.plugins.taglist.TaglistMavenCollector.collect(TaglistMavenCollector.java:50)
	at org.sonar.mojo.InternalMojo.executeCollectors(InternalMojo.java:295)
	at org.sonar.mojo.InternalMojo.processModules(InternalMojo.java:177)
	at org.sonar.mojo.InternalMojo.execute(InternalMojo.java:156)
	at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:451)
	at org.codehaus.mojo.sonar.Bootstraper.executeMojo(Bootstraper.java:82)
	... 20 more