WMI- Error en parametro

[MAXIUM]

Me arroja el siguiente error de parámetros y no se que puede ser.

objWMIService.ExecMethod('Win32_WindowsProductActivation', 'SetProductKey', objInParams);

Código Delphi [-]
program GetWMI_Info;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  ActiveX,
  ComObj,
  Variants;

function VarArrayToStr(const vArray: variant): string;

    function _VarToStr(const V: variant): string;
    var
    Vt: integer;
    begin
    Vt := VarType(V);
        case Vt of
          varSmallint,
          varInteger  : Result := IntToStr(integer(V));
          varSingle,
          varDouble,
          varCurrency : Result := FloatToStr(Double(V));
          varDate     : Result := VarToStr(V);
          varOleStr   : Result := WideString(V);
          varBoolean  : Result := VarToStr(V);
          varVariant  : Result := VarToStr(Variant(V));
          varByte     : Result := char(byte(V));
          varString   : Result := String(V);
          varArray    : Result := VarArrayToStr(Variant(V));
        end;
    end;

var
i : integer;
begin
    Result := '[';
     if (VarType(vArray) and VarArray)=0 then
       Result := _VarToStr(vArray)
    else
    for i := VarArrayLowBound(vArray, 1) to VarArrayHighBound(vArray, 1) do
     if i=VarArrayLowBound(vArray, 1)  then
      Result := Result+_VarToStr(vArray[i])
     else
      Result := Result+'|'+_VarToStr(vArray[i]);

    Result:=Result+']';
end;

function VarStrNull(const V:OleVariant):string; //avoid problems with null strings
begin
  Result:='';
  if not VarIsNull(V) then
  begin
    if VarIsArray(V) then
       Result:=VarArrayToStr(V)
    else
    Result:=VarToStr(V);
  end;
end;


function GetWMIObject(const objectName: String): IDispatch; //create the Wmi instance
var
  chEaten: Integer;
  BindCtx: IBindCtx;
  Moniker: IMoniker;
begin
  OleCheck(CreateBindCtx(0, bindCtx));
  OleCheck(MkParseDisplayName(BindCtx, StringToOleStr(objectName), chEaten, Moniker));
  OleCheck(Moniker.BindToObject(BindCtx, nil, IDispatch, Result));
end;

procedure  Invoke_Win32_WindowsProductActivation_SetProductKey;
var
  objWMIService   : OLEVariant;
  objInvoker      : OLEVariant;
  objInParams     : OLEVariant;
  objOutParams    : OLEVariant;
begin
  objWMIService := GetWMIObject(Format('winmgmts:\\%s\%s',['.','root\CIMV2']));
  objInvoker    := objWMIService.Get('Win32_WindowsProductActivation');
  objInParams   := objInvoker.Methods_.Item('SetProductKey').InParameters.SpawnInstance_();
  objInParams.ProductKey:= '7777755555777775555577777';
  objOutParams  := objWMIService.ExecMethod('Win32_WindowsProductActivation', 'SetProductKey', objInParams);
  Writeln('ReturnValue         '+VarStrNull(objOutParams.ReturnValue));
end;


begin
 try
    CoInitialize(nil);
    try
      Invoke_Win32_WindowsProductActivation_SetProductKey;
      Readln;
    finally
    CoUninitialize;
    end;
 except
    on E:Exception do
    begin
        Writeln(E.Classname, ':', E.Message);
        Readln;
    end;
  end;
end.