Group Policy Error: "The RPC server is unavailable."

RPC uses port 135.

• Open the Group Policy Object Editor snap-in to edit the Group Policy object (GPO) that is used to manage Windows Firewall settings in your organization
• Open Computer Configuration, open Administrative Templates, open Network, open Network Connections, open Windows Firewall, and then open Domain Profile.
• In the details pane, double-click Windows Firewall: Allow remote administration exception.
• In the Windows Firewall: Allow remote administration exception properties dialog box, on the Settings tab, click Enabled or Disabled

http://technet.microsoft.com/en-us/library/cc738900(v=ws.10).aspx