PDF to PDF/A-1b conversion issue

Dear All,

While converting a PDF to a PDF/A-1b with Aspose.Pdf, we run into an issue. The code is trying to embed fonts as per Aspose DEV guide,

https://docs.aspose.com/display/pdfjava/Formatting+PDF+Document#FormattingPDFDocument-EmbeddingFontsinanExistingPDFFile
 
but fails to do so. The server log indicates that the code trying to embed the fonts does run and does not throw any exception.

The code runs on JBoss 7.1 application server residing on Red Hat Linux 6.x with Java 1.7.

Please advise how to ensure that the listed fonts are successfully embedded into the generated PDF/A.  Where does Aspose look for these fonts?

Additionally, there is a non-blocking error reported in the conversion log.
<Problem Severity="Error" Clause="6.7.7" Convertable="True">The instanceID field shall not be specified</Problem></Metadata>

Please also advise how to overcome that error.

Many thanks!

Java code, conversion log, and original PDF attached.