Anyone seen this Output error before?

Has anyone ever seen this Output error before? I'm not sure where to start debugging:

SoapFault exception: [soapenv:Server.generalException] com.adobe.livecycle.assembler.client.ProcessingException: ALC-ASM-S00-002: Failed to execute the DDX - error messages provided. Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -2;

Here is the DDX:

<?xml version="1.0" encoding="UTF-8"?>
                    <DDX xmlns="http://ns.adobe.com/DDX/1.0/">
                      <PDF result="merged">

                         <PDF source="file:///u01/app/adobe/livecycle9/repository/UltraForms/Test/getfile.pdf" />

                         <PDF source="http://formsapp3.dmz.far.org/public/getfile/?file_id=405819|2281536" />

                         <PDF source="http://help.adobe.com/en_US/livecycle/9.0/ddxRef.pdf" />

                      </PDF>
                    </DDX>

The first and third PDFs are fine. For some reason the second file causes the error. I can go straight to the URL and the PDF renders fine.

Any ideas?

- Nathan Dawson