NPE when translating a web content

When trying to add a translation the system throws the following error:

09:04:47,125 ERROR [http-bio-8080-exec-6][render_portlet_jsp:154] java.lang.NullPointerException
at com.liferay.portlet.dynamicdatamapping.storage.Field.getValue(Field.java:168)
at com.liferay.portlet.dynamicdatamapping.storage.Field.getValue(Field.java:162)
at com.liferay.portlet.dynamicdatamapping.util.DDMImpl.getFieldsDisplayValues(DDMImpl.java:171)
at com.liferay.portlet.dynamicdatamapping.util.DDMUtil.getFieldsDisplayValues(DDMUtil.java:77)
at com.liferay.portlet.journal.util.JournalConverterUtil.countFieldRepetition(JournalConverterUtil.java:168)
at com.liferay.portlet.journal.util.JournalConverterUtil.getXML(JournalConverterUtil.java:102)
at com.liferay.portlet.journal.action.EditArticleAction.updateArticle(EditArticleAction.java:616)
at com.liferay.portlet.journal.action.EditArticleAction.processAction(EditArticleAction.java:144)
at com.liferay.portal.struts.PortletRequestProcessor.process(PortletRequestProcessor.java:171)
at com.liferay.portlet.StrutsPortlet.processAction(StrutsPortlet.java:214)
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:70)
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:48)
at com.liferay.portlet.InvokerPortletImpl.invoke(InvokerPortletImpl.java:554)
at com.liferay.portlet.InvokerPortletImpl.invokeAction(InvokerPortletImpl.java:585)
at com.liferay.portlet.InvokerPortletImpl.processAction(InvokerPortletImpl.java:295)
at com.liferay.portlet.PortletContainerImpl._doProcessAction(PortletContainerImpl.java:508)
at com.liferay.portlet.PortletContainerImpl.processAction(PortletContainerImpl.java:115)
at com.liferay.portlet.RestrictPortletContainerWrapper.processAction(RestrictPortletContainerWrapper.java:73)
at com.liferay.portal.kernel.portlet.PortletContainerUtil.processAction(PortletContainerUtil.java:114)
at com.liferay.portal.action.LayoutAction.processLayout(LayoutAction.java:356)