BOE XI R2 Error on failed instance: Unknown Database Connector Error

I have a recurring job that runs against a high availability instance of our SAP production server. This job runs every 15 minutes to make sure that the HAS reporting instanace is available to my BOE environment for reporting. This morning, one of my recurring instances failed and the associated message was "Unknown Database Connection Error." The application and system event logs on my BOE server for the period immediately prior to the instance failure did not show any issues or unusual behavior. Basis reviewed AS400 logs for the SAP instance and didn't see anything there either.

Has anyone experienced a similar error nessage for a failed instance in this sort of a scenario? The next recurring instance, and so far all subsequent runs, have been successful.