DPM Error ID 3123

Failed to update permissions used for end-user recovery on FILE-SRV.xxx.local. Permissions update failed for the following reason: (ID: 3123)

This issue took a while to find a solution for, but it worked for me.
Open Server Manager on the DPM server and expand Roles, File Services, Share and Storage Management.
Remove any shares with the \\?\C :\ in the Local path if they are preceeded with a red X. (DPM will recreate these correctly afterwards).
Resume backup.

DCOM Error, Event ID: 10005

To resolve the following System Error in the Event Viewer:

DCOM got error "The service cannot be started, either because it is disabled or because it has no enabled devices associated with it. " attempting to start the service with arguments "" in order to run the server:

1 Go to Administrative Tools
2 Select Component Services
3 Expand out the tree to show the following: \Console Root\Component Services\Computers\My Computer\DCOM Config\netman
4 Right click the netman node and choose Properties 
5 Select the Security tab from the window
6 In the Launch and Activation Permissions frame, click the Customize radio button
7 In the Launch and Activation Permissions frame, click the Edit button
8 Select (or add) the user NETWORK SERVICE in the Group or user names list
9 Tick the Allow checkbox for:

  • Local Launch 
  • Remote Launch 
  • Local Activation 
  • Remote Activation

10 Click OK to accept your changes.
11 Click OK again to return to the component services window.
12 Close the Component Services window