Now, when I try to save my Anti Spam configuration in FP 2010 i get this error: “The server threw an exception. (Exception from HRESULT: 80010105 (RPC_E_SERVERFAULT))”

This error is coming due to duplicate IP.

Removing the duplicate IP manually.Run the command in Exchange mangement Shell

For listing the IP block list entry type

“Get-IPBlocklistEntry” This will show the all block list IP’s which you saved there rectify the duplicate IP from there and remove manually.

Manually removing command

As you add entries to the IP Block list, Exchange automatically assigns IDs to the entries. To remove an address from the IP Block list using the Shell, you must specify this ID. However, an easier way to remove an address is to pipeline the output of the Get-IPBlockListEntry cmdlet to the Remove-IPBlockListEntry cmdlet. For example, if you want to remove the IP address from your IP Block list, run the following command:

Get-IPBlockListEntry -IPAddress | Remove-IPBlockListEntry

If you want to remove a range, specify an IP address that is within that range for the IPAddress parameter of the Get-IPBlockListEntry cmdlet. The following example shows how you can remove the subnet

Get-IPBlockListEntry -IPAddress | Remove-IPBlockListEntry

You can see the more details from below link