Your version of DP is way out of support, so, I really don't know if I am going to be able to help much. Maybe one of the other forum members can provide some help
From your screenshot of 'chkconf', the RETVAL*8561 means
# omnigetmsg 12 8561
[12:8561] The selected Data Protector Single Mailbox integration is not configured.
Data Protector Single Mailbox integration has to be configured before first crea
tion of backup specification.
1. Create Single Mailbox Configuration from "Configure Single Mailbox" dialog.
2. See Data Protector documentation on configuring MS Single Mailbox integration
I suspected this when I saw your 'getconfig' output
Domain <null>
Username <null>
Password <null>
I don't know if your configuration file got deleted or corrupted, but the Single Mailbox integration is going to need to be redone