SSIS ScriptTask change Value property of Variable

Question

I try to simply change value of SSIS variable doing this code in ScriptTask:

        string path = Dts.Connections["BazyPobrane"].ConnectionString.ToString();
        string[] nameZIParray = Directory.GetFiles(path, "*.ZIP");
        string[] nameRARarray = Directory.GetFiles(path, "*.RAR");

        foreach (string nameZIP in nameZIParray) //search new ZIP
        {
            if (File.GetCreationTime(nameZIP) > DateTime.Now.AddDays(-1))
            {
                Dts.Variables["User::NazwaPliku"].Value = Path.GetFileName(nameZIP);
            }

        }
        foreach (string nameRAR in nameRARarray) //search new RAR
        {
            if (File.GetCreationTime(nameRAR) > DateTime.Now.AddDays(-1))
            {
                Dts.Variables["User::NazwaPliku"].Value = Path.GetFileName(nameRAR);
            }

        }
        Dts.TaskResult = (int)ScriptResults.Success;

After executing ScriptTask it simply don't change the variable Value. Debug mode seems fine. Maybe i miss some component settings? Thx!