CU5 to CU6 upgrade error

Hello,

Upgrading from CU5 to CU6 I ran into this error during the installation. Has anyone seen this before or knows a way round it:

Error:
The following error was generated when "$error.Clear(); 
          $name = [Microsoft.Exchange.Management.RecipientTasks.EnableMailbox]::DiscoveryMailboxUniqueName;
          $dispname = [Microsoft.Exchange.Management.RecipientTasks.EnableMailbox]::DiscoveryMailboxDisplayName;
          $dismbx = get-mailbox -Filter {name -eq $name} -IgnoreDefaultScope -resultSize 1;
          if( $dismbx -ne $null)
          {
          $srvname = $dismbx.ServerName;
          if( $dismbx.Database -ne $null -and $RoleFqdnOrName -like "$srvname.*" )
          {
          Write-ExchangeSetupLog -info "Setup DiscoverySearchMailbox Permission.";
          $mountedMdb = get-mailboxdatabase $dismbx.Database -status | where { $_.Mounted -eq $true };
          if( $mountedMdb -eq $null )
          {
          Write-ExchangeSetupLog -info "Mounting database before stamp DiscoverySearchMailbox Permission...";
          mount-database $dismbx.Database;
          }

          $mountedMdb = get-mailboxdatabase $dismbx.Database -status | where { $_.Mounted -eq $true };
          if( $mountedMdb -ne $null )
          {
          $dmRoleGroupGuid = [Microsoft.Exchange.Data.Directory.Management.RoleGroup]::DiscoveryManagement_InitInfo.WellKnownGuid;
          $dmRoleGroup = Get-RoleGroup -Identity $dmRoleGroupGuid -DomainController $RoleDomainController -ErrorAction:SilentlyContinue;
          if( $dmRoleGroup -ne $null )
          {
            trap [Exception]
            {
              Add-MailboxPermission $dismbx -User $dmRoleGroup.Name -AccessRights FullAccess -DomainController $RoleDomainController -ErrorAction SilentlyContinue;
              continue;
            }
            
            Add-MailboxPermission $dismbx -User $dmRoleGroup.Identity -AccessRights FullAccess -DomainController $RoleDomainController -WarningAction SilentlyContinue;
          }
          }
          }
          }
        " was run: "Microsoft.Exchange.Data.ApplicationLogic.Cafe.BackEndLocatorException: Server Locator Service call had a communication error. ---> Microsoft.Exchange.Data.Storage.ServerLocator.ServerLocatorClientTransientException: Server Locator Service call had a communication error. ---> System.ServiceModel.EndpointNotFoundException: Could not connect to net.tcp://styx2.corp.alpha-data.com:64337/Exchange.HighAvailability/ServerLocator. The connection attempt lasted for a time span of 00:00:04.0683258. TCP error code 10061: No connection could be made because the target machine actively refused it 192.168.2.224:64337.  ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 192.168.2.224:64337
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.ServiceModel.Channels.SocketConnectionInitiator.ConnectAsyncResult.OnConnect(IAsyncResult result)
   --- End of inner exception stack trace ---

Server stack trace: 
   at System.Runtime.AsyncResult.End[TAsyncResult](IAsyncResult result)
   at System.ServiceModel.Channels.ServiceChannel.SendAsyncResult.End(SendAsyncResult result)
   at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
   at System.ServiceModel.Channels.ServiceChannelProxy.InvokeEndService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
   at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]: 
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
   at ServerLocator.EndGetActiveCopiesForDatabaseAvailabilityGroup(IAsyncResult result)
   at Microsoft.Exchange.Data.Storage.ServerLocator.ServerLocatorServiceClient.EndGetActiveCopiesForDatabaseAvailabilityGroup(IAsyncResult result)
   --- End of inner exception stack trace ---
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.MailboxServerLocator.EndGetServer(IAsyncResult result)
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.BackEndLocator.GetBackEndServerByDatabase(ADObjectId database, OrganizationId organizationId, SmtpAddress primarySmtpAddress)
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.BackEndLocator.<>c__DisplayClass3.<getbackendserver>b__2()
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.BackEndLocator.CallWithExceptionHandling[T](Func`1 actualCall)
   --- End of inner exception stack trace ---
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.BackEndLocator.CallWithExceptionHandling[T](Func`1 actualCall)
   at Microsoft.Exchange.Management.RecipientTasks.SetMailboxPermissionTaskBase.PrepareDataObject()
   at Microsoft.Exchange.Configuration.Tasks.SetTaskBase`1.InternalValidate()
   at Microsoft.Exchange.Configuration.Tasks.SetRecipientObjectTask`3.InternalValidate()
   at Microsoft.Exchange.Management.RecipientTasks.SetMailboxPermissionTaskBase.InternalValidate()
   at Microsoft.Exchange.Management.RecipientTasks.AddMailboxPermission.InternalValidate()
   at Microsoft.Exchange.Configuration.Tasks.Task.<processrecord>b__b()
   at Microsoft.Exchange.Configuration.Tasks.Task.InvokeRetryableFunc(String funcName, Action func, Boolean terminatePipelineIfFailed)".</processrecord></getbackendserver>

Best regards,

David