API Json 修改分录数据

//
string sJson = "{\"Creator\":\"第三方调用标识\",\"NeedUpDateFields\":[],\"Model\":{\"FID\":\"100194\","+
"\"FEntityDetail\":["+
"{\"FEntryID\":\"100358\"}," +
"{\"FEntryID\":\"100359\"}," +
"{\"FEntryID\":0," +
"\"FMATERIALID\":{\"FNumber\":\"L.FREIGHT\"}," +
"\"FPRICEUNITID\":{\"FUnitID\":\"10101\"}," +
"\"FPriceQty\":\"1\"," +
"\"FPrice\":\"1674.84\"," +
"\"FTaxPrice\":\"1674.84\"}" +
//"{\"FEntryID\":\"0\","+
// "\"FMATERIALID\":{\"FNumber\":\"L.INSURANCE\"},"+
// "\"FPRICEUNITID\":{\"FNumber\":\"03\"},"+
// "\"FPriceQty\":\"1\","+
// "\"FPrice\":\"66.22\","+
// "\"FTaxPrice\":\"66.22\"}"+

"]}}";

string strItemName = "AR_receivable";
object jsonInfo = client.Execute("Kingdee.BOS.WebApi.ServicesStub.DynamicFormService.Save",
new object[] { strItemName, sJson });

调用API修改分录数据,我不改原先的分录,而是新增分录数据
现在报下面的异常

请总部大神指教!