Error while converting Image -to- PDF and then to PDF/A

Hi,

I'm trying to convert a Image format(JPEG,bmp,tiff) to PDF and then to PDF/A. I could able to convert Image to PDF successfully.

I'm getting the below error while converting the PDF(that was generated) to PDF/A.

Caused by: com.adobe.livecycle.output.exception.OutputException: Input Document is a already flat PDF Document
at com.adobe.printSubmitter.PrintServer.transformPDF(PrintServer.java:307)
at com.adobe.printSubmitter.service.OutputServiceImpl.transformPDFInTxn(OutputServiceImpl.ja va:518)
at com.adobe.printSubmitter.service.OutputServiceImpl$4.doInTransaction(OutputServiceImpl.ja va:481)
... 106 more
Error OCCURRED: ALC-DSC-000-000: com.adobe.idp.dsc.DSCException: Internal error.

Please give me the solution to convert PDF to PDF/A?