[xwiki-users] object template and groovy

I have created a XWiki class as described in the FAQTutorial ( http://platform.xwiki.org/xwiki/bin/view/DevGuide/FAQTutorial), I have then modified the Document Sheet code, and I have tried to use groovy scripting instead of velocity. However when creating a new object, I get the error Failed to execute the [groovy] macro org.xwiki.rendering.macro.MacroExecutionException: You don't have the right to execute this script whereas the same works if I translate the code into velocity. Editing an existing page with the groovy script works fine, it only fails when creating a new document. Any idea? thanks Vito