constantly failing to delete files (locks issue)

All the time on windows 7 (very annoying and unproductive):

Failed to execute goal org.codehaus.mojo:nbm-maven-plugin:3.5-SNAPSHOT:branding (branding) on project branding: Error creating branding: Directory C:\Users\kahloutg\Documents\NetBeansProjects\MavenCRUDSample\branding\target\nbm\netbeans\foobar\core\core.jar\org\netbeans\core unable to be deleted. -> [Help 1]

To see the full stack trace of the errors, re-run Maven with the -e switch.
Re-run Maven using the -X switch to enable full debug logging.

For more information about the errors and possible solutions, please read the following articles:
[Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

After correcting the problems, you can resume the build with the command
mvn <goals> -rf :branding

Sample crud nb app attached.