I passed by this experience when i was setting a new protection group using DPM 2012 for the latest SQL database server 2012. As per Microsoft System Center 2012 - Data Protection Manager Release Notes http://technet.microsoft.com/en-us/library/hh848297.aspx DPM 2012 should backup and recover SQL 2012 Databases except if the AlwaysOn feature is enabled. The AlwaysOn feature is not supported under the current DPM 2012 RTM but expected to be fully supported with the release of the System Center 2012 SP1 (expected in the next few weeks).
Although my SQL 2012 DB AlwaysOn feature wasn't enabled the DPM job always fails immediately after it starts, Consistency check also didn't work as well. After some investigation and several trials it turns out that the NT AUTHORITY\SYSTEM account on the SQL server needs to have Sysadmin role/right
Briefly, To backup and recover SQL 2012 workload under DPM 2012 RTM
Make sure the AlwaysOn feature is not enabled (Currently DPM 2012 RTM doesn't support it)
Grant the SQL NT AUTHORITY\SYSTEM account SysAdmin Right.
Remove the Protection group and add it again after applying the above changes.
