We get an unexpected error when viewing invoices in buyer work center

In BWC, we query a PO, use the Actions drop down to select View Invoices.  In the view invoices window we select an invoice where the Payment value is Multiple.  We click on the Multiple hyper link.  The view Payment window show multiple Payments.  in a payment record we click on the Hyper link in the Invoice column that has a value of Multiple.  The system does not return ant invoice records for this payment.  The window has an error, "An unexpected error has occurred. Please try again later and if the problem persists, please contact your system administrator.  We