Assemble PDF's located in Network folder

Hi,

I am trying to assemble PDF's which are located in a network folder..

<?xml version="1.0"?>

<DDX xmlns="http://ns.adobe.com/DDX/1.0/">

     <PDF result="PDFA.pdf">

          <PDF source="\\w2msmossmgn02\SharedFolder\PID_APR_P111556.pdf"/>

          <PDF source="\\w2msmossmgn02\SharedFolder\PID_P111556.pdf"/>

     </PDF>

</DDX>

when the assembler service is invoked with the above DDX, i get an error as below,

com.adobe.internal.ddxm.DDXMException: com.adobe.internal.pdfm.CollateralNotFoundException:

DDXM_S14017: A <PDF> source document is required, but no documents were found for {PDF source="\\w2msmossmgn02\SharedFolder\PID_APR_P111556.pdf" baseDocument="true"}.

I have also tried giving the files names as specified in the DDXREF help file as below,

file:///dir-path/filename  (file:///w2msmossmgn02/SharedFolder/PID_APR_P111556.pdf) but it didn't work either.

Can some one pls help?

Thank you,

Sandeep.