Hudson understands PMD's Copy Paste Detector (CPD) analysis report XML format. When this option is configured Hudson shows the CPD analysis results in different views: historical result trend, module and package statistics, web UI for viewing analysis reports and warnings, and so on.
You need to set up your build to run CPD in order to use this feature - this Hudson plug-in does not perform the actual analysis! This plug-in is not invoked for failed builds, it is only called for stable or unstable builds (i.e., a build with failed tests).