I ran into a issue deploying Data Protection Manager 2010 RC for a customer.

Where the agent installation failed with Error ID 270  but completed on one machine.

Agent install was default install , so no preinstall agents

And started fine and completed without errors

But the agent communication from the client to the DPM server didnt work , verified install account had permission on remote host and everythinig was up and running

On the agent machine the only hints at a error was the system event log

The server {C4EBD674-1457-4B79-BE30-B04735AED9D1} did not register with DCOM within the required timeout.

DPMRACurr didnt give any hints to a reson of why the agent is unable to communicate with the DPM server.

On the Data Protection Manager server i got the following error when the agents tries to talk home

DCOM got error "2148007941" from the computer xSP01.demo.local when attempting to activate the server:
{C4EBD674-1457-4B79-BE30-B04735AED9D1

After some digging around for clue the error was only visible on 2008 server but not on the clean install i did for testing purpose , so after looking though the machines i found out that the machine that failed had the same SID so the deployment job that installed the machine didnt run sysprep on completion.

So always remember to sysprep your servers before deployment

to fix the issue uninstall the agent , disjoing the server from the domain , and run newsid and join domain again.