Answer
Work through the XML-generation chain step by step: confirm the 'Create Xml' checkbox is enabled in that report's own Report Definition; check the report's RDF for the actual XML-generation code and confirm the Report_SYS.Finish_Xml_Report line is present and not skipped by a conditional (an IF block that could bypass it under some conditions); check that the RDF has a do_xml_ BOOLEAN variable driven by Report_SYS.Should_Generate_Xml (which reflects the Create Xml checkbox setting from the first step); confirm the correct report ID is actually being passed through those checks; check archive_tab to confirm the archive item for that report exists; and finally check xml_report_data_tab for a record matching the result key, with the generated XML actually present in its DATA or ZDATA column. Working through this sequence pinpoints exactly which stage of XML generation and storage is where the chain is actually breaking, rather than guessing from the generic error message alone.