- An error has occurred. org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.grails.gsp.GroovyPagesException: Error processing GroovyPageView: [views/treeVersion/validate.gsp:14] Error executing tag <g:render>: [views/treeVersion/_validateContent.gsp:52] Error executing tag <tree:commonSynonyms>: Cannot get property 'namePath' on null object