JSF / PrimeFaces : nouveau thème

Bonjour,

J'ai voulu modifier le thème PrimeFaces de mon appli et plus rien ne marche !
J'ai remis mon appli dans sont état d'avant mais ça ne marche plus.
Voici le message au lancement de l'appli :

Merci de votre aide !!!

ant -f C:\\Users\\Denis\\Documents\\NetBeansProjects\\eMarket -Dnb.internal.action.name=run -Ddirectory.deployment.supported=true -DforceRedeploy=false -Dnb.wait.for.caches=true -Dbrowser.context=C:\\Users\\Denis\\Documents\\NetBeansProjects\\eMarket run
C:\Users\Denis\Documents\NetBeansProjects\eMarket\nbproject\build-impl.xml:797: The libs.CopyLibs.classpath property is not set up.
This property must point to
org-netbeans-modules-java-j2seproject-copylibstask.jar file which is part
of NetBeans IDE installation and is usually located at
<netbeans_installation>/java<version>/ant/extra folder.
Either open the project in the IDE and make sure CopyLibs library
exists or setup the property manually. For example like this:
ant -Dlibs.CopyLibs.classpath=a/path/to/org-netbeans-modules-java-j2seproject-copylibstask.jar
BUILD FAILED (total time: 0 seconds)