JSON串问题

try
{
ApiClient client = new ApiClient(WebAPIConfig.CloudUrl);
bool ret = client.Login(WebAPIConfig.DbId, WebAPIConfig.UserName, WebAPIConfig.PassWord, WebAPIConfig.Lcid);
if (ret)
{
string strJson = JsonConvert.SerializeObject(saveModel);
//string abc = "{\"Creator\":\"Demo\",\"NeedUpDateFields\":[\"\"],\"Model\":{\"FID\":0,\"FBUSINESSTYPE\":\"NORMAL\",\"FDATE\":\"2016- 06-07 14:31:51.129\",\"FBillTypeID\":{\"FNumber\":\"XSDD01_SYS\"},\"FsaleDeptID\":{\"FNumber\":\"BM000001\"},\"FcustID\": {\"FNumber\":\"CUST0001\"},\"FSalerID\":{\"FNumber\":\"20140822\"},\"FSaleOrderFinance\":{\"FExchangeRate\":1},\"FSaleOrderEntry\":[{\"FID\":0,\"FMaterialID\":{\"FNUMBER\":\"1.01.0012222\"},\"FQty\":3,\"FBASEUNITQTY\":3,\"FTaxPrice\":200,\"FPriceUnitQty\":3},{\"FID\":0,\"FMaterialID\":{\"FNUMBER\":\"1.01.0012222\"},\"FQty\":9,\"FBASEUNITQTY\":9,\"FTaxPrice\":200,\"FPriceUnitQty\":9}]}}";
object[] subInfo = new object[]
{
sFormId,
strJson
//abc
};
var strRet = client.Execute("Kingdee.BOS.WebApi.ServicesStub.DynamicFormService.Save", subInfo);
WriteLog.WriteLogAndTime("WebAPI Msg" + strRet);

RetObject retObject = JsonConvert.DeserializeObject(strRet);
if (!retObject.Result.ResponseStatus.IsSuccess)
{
throw new Exception("接口错误！");
}
}
}
catch (Exception ex)
{
WriteLog.WriteLogAndTime("WebAPI接口错误" + ex.Message);
throw new Exception("接口错误" + ex.Message);
}
}

用绿色的JSON串abc可以把数据传入销售订单，但这个JSON串是通过蓝色字符串string strJson = JsonConvert.SerializeObject(saveModel);生成的，请教大家这是什么原因？谢谢！

错误提示：
"{\"Result\":{\"ResponseStatus\":{\"ErrorCode\":500,\"IsSuccess\":false,\"Errors\":[{\"FieldName\":\"\",\"Message\":\"第1行分录的第1行子分录，计划发货日期不允许小于单据日期！\"},{\"FieldName\":\"\",\"Message\":\"第2行分录的第1行子分录，计划发货日期不允许小于单据日期！\"},{\"FieldName\":\"AbstractInteractionResult\",\"Message\":\"AbstractInteractionResult.InteractionContext is null\"}]},\"Id\":\"\"}}"