AutoInvoice Failing for PROJECTS Invoice (interface_line_attribute8 is null)

We are running the auto invoice process for an invoice that was interfaced from the r12.1.3 Projects (Grants) module.  The Interface from PA -> AR process was successful and the invoice record shows in the ra_interface_lines_all table.

However when we try to run the AR AutoInvoice program it fails with the following message....

                                          AutoInvoice Validation Report                             Date: 23-FEB-2011 18:31
                                                                                                             Page:      1 of       2
Auto Invoice Request Id 1086797
          Batch Source: PROJECTS INVOICES

Transaction Flexfield: PROJECTS INVOICES: 8.1.8.461001 WTD DIRECTOR OFFICE.Nevers, Barbara A.         1.Line

Type                 Bill to Customer Name                    Item Description                         Currency               Amount
-------------------- ---------------------------------------- ---------------------------------------- ----------- -----------------
Invoice              WA ST DEPT OF ECOLOGY HQ                 Test Event                               USD                 1,000.00