The installation step is almost the same as DPM 2010 Beta. You can refer to http://www.ms4u.info/2009/10/installing-dpm-2010-beta.html .
For those, who has install DPM 2010 into Windows Server 2008 R2, you will notice this error on DPM 2010 Beta: http://www.ms4u.info/2009/11/dpm-2010-beta-failed-to-install-in.html . Microsoft has fixed this issue and the installation completed without any error.
However, once you have restart the DPM server and you try to access the DPM console, you will receive this error message:- "Unable to connect to DPM (IDM:948)"
So i have decided to check on the DPM service. DPM service is dependent to SQL Express and i have found that the SQL service failed to start when using the assigned account.
To fix this issue, i have set both SQL server services to Local system account. Then restart the SQL services and DPM services.
Note:- This problem not happen all the time.