如何在Windows上更新Ruby Gems 2.2.3时修复错误？

Question

这是错误：

            var startupPath = System.IO.Path.GetDirectoryName(
        System.Reflection.Assembly.GetEntryAssembly().Location);
        OleDbConnection con = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + startupPath + "\\baza.accdb");
        con.Open();
        OleDbCommand comm = con.CreateCommand();
        comm.CommandText = "Update Korisnik Set Password = '"+ Microsoft.VisualBasic.Interaction.InputBox("Izaberite novu šifru", "Filmoteka", "", -1, -1) + "' Where Username = 'admin'";
        comm.ExecuteNonQuery();            
        con.Close();

当我尝试使用以下命令更新Rails时

ERROR : loading commend: install (ArgumentError)
                 unkoun encoding name - CP720
ERROR: While executing gem ... (NoMethodError)
                undefined method 'invoke_with_build_args' for nil:NilClass

如何解决此错误？