Hi,
It is a known issue and working as designed.
Workaround:-
1. Open services.msc and go to properties of the "Symantec Endpoint Protection Manager" Service
2. Click on the Logon tab and click on "This account"
3. Enter the Administrator credentials
4.Click on OK and restart the SEPM service
5. Now login to the SEPM console and Deploy it using the "Find Unmanaged computers" and it will be successful.
Reason : You have following machine in the network.
A. Windows Server 2008 r2
B. Windows 7 64bit
When you logon to the A machine as administrator the SEPM runs using the local sysytem account. In the Windows Server 2008 r2 if you try to deloy any SEP package using local system account from SEPM ,it will not have the access to Remote registry of the client and you will get "Access denied" which can be seen in the logs. Therefore running the SEPM using the Administrator Credentials for SEPM services manualy will give access to the remote registry of the client.