Getting an error message while building PhoneGapSample in blackberry Webworks

Question

I am working on PhoneGap BlackberryWebWorks i have install BlackBerry WebWorks plug-in:2.5.1 and Blackberry WebWorks SDK:2.0.0. and PhoneGap 0.9.4.but while building the project in eclipse i am getting the following error

  Errors occurred during the build.   Errors running builder 'Faceted Project Validation Builder' on project 'PhoneGapSample'.   Could not initialize class org.eclipse.jst.j2ee.project.facet.IJ2EEFacetConstants  

I am not getting any idea how to proceed ahead to remove this error.If any one have any idea about this. it will help me to overcome from this error. Thanks, Sagar.