NullPointerException when report are generated on ... Windows

Strange bug occurs on Windows (works fine on MacOSX)...
If the project which javancss-maven-plugin tries to report is located at the root of a drive (z:/) it works fine...
looks something related to the length of the path ?!?

NPE is within javancss code... not plugin code.
Anyhow this must be solved.

Trace of a mvn javancss:report -X on javancss-maven-plugin :

[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\AbstractNcssReportGenerator.java
[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\ModuleReport.java
[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\NcssAgregateReportGenerator.java
[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\NcssExecuter.java
[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\NcssReportGenerator.java
[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\NcssReportMojo.java
[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\NcssViolationCheckMojo.java
[DEBUG] Including for parsing : C:\src\javancss-maven-plugin\src\main\java\org\codehaus\mojo\javancss\NumericNodeComparator.java
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] An error has occurred in JavaNCSS Report report generation.

[INFO] ------------------------------------------------------------------------
[DEBUG] Trace
org.apache.maven.lifecycle.LifecycleExecutionException: An error has occurred in JavaNCSS Report report generation.
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:559)
.../...
Caused by: java.lang.NullPointerException
at java.io.File.<init>(File.java:194)
at javancss.Javancss.<init>(Javancss.java:553)
at org.codehaus.mojo.javancss.NcssExecuter.execute(NcssExecuter.java:79)