Symptoms
- When protection of an SQL server in DPM is configured, DPM shows critical error “Unable to configure protection”
Resolution
- Open SQL Management Studio on database server
- Navigate to Security > Logins
- Right click on NT AUTHORITY\SYSTEM and click properties
- Under Server Roles, check the sysadmin box and click ok
- In DPM, right click on each critical job and select run Configure protection job again
Liam Matthews IT 
Awesome – clear, conscise, to the point. Thanks very much for sharing. Did the job.