I Started a new Project and everything work.
values["DT_Update"] = new XVar(DateTime.Now);
values["CD_User"] = XSession.Session["UID"];
values["DSURLEnd"] = HttpContext.Current.Request.Url.AbsoluteUri;
var ext = "";
var cardName = String.Format("Carta{0}{1}{2}", XSession.Session["UID"].ToString(), values["CD_MeuJogo"].ToString(), values["SQ_NoImg"].ToString());
var newcardName = String.Format("Cartoes/{0}/" + "{1}", XSession.Session["UserID"].ToString(), cardName);
var thumbcardName = String.Format("Cartoes/{0}/" + "{1}{2}", XSession.Session["UserID"].ToString(), cardName, "thumb");
// get information about uploaded files
var fileArray = MVCFunctions.my_json_decode(values["IM_FotoCard"]);
values["IM_FotoCard"] = MVCFunctions.my_json_encode(fileArray);
// rename files
for(int i = 0; i < fileArray.Count(); i++)
{
var fileName = fileArray[i]["name"];
var themubName = fileArray[i]["thumbnail"];
ext = System.IO.Path.GetExtension(fileArray[i]["name"]);
var newFileName = String.Format("{0}{1}", newcardName, ext);
var newThemubName = String.Format("{0}{1}{2}", newcardName, "thumb", ext);
System.IO.File.Move(MVCFunctions.getabspath(fileName), MVCFunctions.getabspath(newFileName));
System.IO.File.Move(MVCFunctions.getabspath(themubName), MVCFunctions.getabspath(newThemubName));
fileArray[i]["name"] = newFileName;
fileArray[i]["usrName"] = String.Format("{0}{1}", cardName, ext);
fileArray[i]["thumbnail"] = newThemubName;
}
// update values of the field that stores file names
values["IM_FotoCard"] = MVCFunctions.my_json_encode(fileArray);
var newQRName = String.Format("{0}{1}", newcardName, ext);
values["DS_URLImg"] = String.Format("{0}{1}{2}{3}", "HTTP://", HttpContext.Current.Request.Url.Authority, "/" ,newQRName);