CosDictionary expected, found class com.adobe.internal.pdftoolkit.core.cos.CosNumeric

Hi,

I'm trying to merge xfa form with pdf using assembler service. For some pdf's it is working fine and for some I'm receiving the following error.

CosDictionary expected, found class com.adobe.internal.pdftoolkit.core.cos.CosNumeric, object Number of invalid cosObject:1036

Can anyone help me out.

Code used to merge in Assembler service:

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

  <PDF result="outDoc">

    <PDF source="coverpage" baseDocument="true">

      <NoXFA/>

    </PDF>

    <PDF source="inPDFDoc"/>

    <NoForms/>

  </PDF>

  <?ddx-source-hint name="coverpage"?>

  <?ddx-source-hint name="inPDFDoc"?>

</DDX>

Image of the error:

Thanks in advance..