DPM server 2010 Attach agent error : administrator privileges missing

I’m hoping you would be able to help me out with this little problem I’m having.

I installed DPM 2010 in our test environment to test backups on Exchange 2010 servers.

The environment includes :

1xDC

2x Exchange Server 2010

1x DPM 2010 server

All of these are running on Microsoft server 2008 R2 Virtual machines. The host machines are using Hyper-v.

So the problem goes like this :

1- I tried to install the agents from the DPM server GUI, which failed saying I didn’t have the correct permissions.

2- So then I tried the manual installation using the commands from : the Microsoft site http://technet.microsoft.com/en-us/library/bb870935.aspx

3- The agent installation worked but when I get to attaching the agents to the DPM server it still gives me the error saying that the specified account does not have administrator rights.

4- I tried the Domain admin, users who are domain admin + local admin, single local admins.

5- I have turned off the windows firewall and made sure all the services are running.

So now I’m out of ideas and really need help, the agent attach to the DPM server is the last thing that is holding me back from deploying everything to the production site. Any help would be really appreciated.