Caused by: org.apache.fop.fo.ValidationException: Property ID "chapter-refid-3.1" (found on "fo:block") previously used; ID values must be unique within a document! (See fo:block, id=chapter-refid-3.1)
	at org.apache.fop.events.ValidationExceptionFactory.createException(ValidationExceptionFactory.java:38)
	at org.apache.fop.events.EventExceptionManager.throwException(EventExceptionManager.java:58)
	at org.apache.fop.events.DefaultEventBroadcaster$1.invoke(DefaultEventBroadcaster.java:173)
	at com.sun.proxy.$Proxy77.idNotUnique(Unknown Source)
	at org.apache.fop.fo.FObj.checkId(FObj.java:202)
	at org.apache.fop.fo.FObj.startOfNode(FObj.java:183)
	at org.apache.fop.fo.flow.Block.startOfNode(Block.java:145)
	at org.apache.fop.fo.FOTreeBuilder$MainFOHandler.startElement(FOTreeBuilder.java:337)
	at org.apache.fop.fo.FOTreeBuilder.startElement(FOTreeBuilder.java:179)
	at org.apache.cocoon.xml.AbstractXMLPipe.startElement(AbstractXMLPipe.java:95)
	at org.apache.cocoon.xml.AbstractXMLPipe.startElement(AbstractXMLPipe.java:95)
	at org.apache.cocoon.transformation.I18nTransformer.startElement(I18nTransformer.java:1185)
	at org.apache.xml.serializer.ToXMLSAXHandler.closeStartTag(ToXMLSAXHandler.java:206)
	at org.apache.xml.serializer.ToSAXHandler.flushPending(ToSAXHandler.java:279)
	at org.apache.xml.serializer.ToXMLSAXHandler.endElement(ToXMLSAXHandler.java:245)
	at org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:1401)
	at org.apache.xalan.templates.ElemApplyTemplates.transformSelectedNodes(ElemApplyTemplates.java:395)
	at org.apache.xalan.templates.ElemApplyTemplates.execute(ElemApplyTemplates.java:178)
	at org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(TransformerImpl.java:2402)
	at org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:1376)
	at org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(TransformerImpl.java:2402)
	at org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:1376)
	at org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(TransformerImpl.java:2402)
	at org.apache.xalan.templates.ElemTemplate.execute(ElemTemplate.java:394)
	at org.apache.xalan.templates.ElemCallTemplate.execute(ElemCallTemplate.java:248)
	at org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(TransformerImpl.java:2402)
	at org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:1376)
	at org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(TransformerImpl.java:2402)
	at org.apache.xalan.transformer.TransformerImpl.applyTemplateToNode(TransformerImpl.java:2272)
	at org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1358)
	at org.apache.xalan.transformer.TransformerImpl.run(TransformerImpl.java:3449)
	at org.apache.xalan.transformer.TransformerHandlerImpl.endDocument(TransformerHandlerImpl.java:408)
	at org.apache.cocoon.xml.AbstractXMLPipe.endDocument(AbstractXMLPipe.java:56)
	at org.apache.cocoon.transformation.TraxTransformer.endDocument(TraxTransformer.java:586)
	at org.apache.cocoon.xml.AbstractXMLPipe.endDocument(AbstractXMLPipe.java:56)
	at org.ametys.odf.export.pdf.FOProgramsGenerator.generate(FOProgramsGenerator.java:111)
	at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.processXMLPipeline(AbstractProcessingPipeline.java:574)