I read a few posts about opening port 135 to enable LanSweeper to read it's data through Windows Firewall. Yet port 135 is open by default, even when the Firewall is running.
If LanSweeper is not able to gather the data from the client (and gives the error:
The RPC server is unavailable. (Exception from HRESULT: 0x800706BA) ), the problem is most likely caused by Remote Administration not being allowed.
To enable it:
netsh firewall set service RemoteAdmin enable
Source:
http://msdn2.microsoft.com/en-us/library/aa389286.aspx