Simple query with Beforereport trigger won't complete normally and won't post-process.

Oracle Apps 12.1.3

BI Publisher is terminating in the Concurrent Manager with an error, but there's no error message, it's producing a valid XML file, and the resulting file won't merge with the Excel Template I've defined for it when I click on output.  I can take the resulting file, load it as the preview file, and it will preview.

I have custom PL/SQL package which is using a beforetrigger to populate a custom table (based on an approach I saw in CSTRITRV_XML -- Intransit Inventory) , then prints off data in the custom table for the given concurrent request id via the Data Def XML query.  The beforetrigger works in PL/SQL Developer test script, but from the concurrent manager, the application is erroring out with no message and the OPP manager isn't being called to process the output.  I believe that the error being generated is preventing the OPP manager from picking it up.  A valid file is being