Since version 1.2.1, it is not possible the export to HTML. the exception below is thrown, but there is no way to set folder.
net.sf.jasperreports.engine.JRException: Image file cannot be written to disk. When saving the document to a stream either HtmlExportImagesFolder should be specified or custom streams should be provided via HtmlExportImageSaving event handler. Please see documentation for details.
at com.aspose.words.jasperreports.AWAbstractExporter.exportReport(Unknown Source)