Steps:
Copy the following file in DPM server
In the Enter Data Protection Manager Computer Name dialog box, type the name of the computer for which you want end-user recovery data in Active Directory Domain Services, and then click OK.
Type the DNS domain name of the DPM computer for which you want end-user recovery data in Active Directory Domain Services, and then click OK.
In the Active Directory Configuration for Data Protection Manager dialog box, click OK.
Wait for a while, it will then show you the result.
Once extended, you can then enable the end user recovery by:
In DPM Administrator Console, on the Action menu, click Options.
In the Options dialog box, on the End-user Recovery tab, select the check box for the Enable end-user recovery option, and then click OK.