采购退料单点击删除后出现如下提示，请各位大神指点一下，谢谢

[{"operation":"PUR_MRB_List.AfterConfirm"}]

发生时间： 13:48:45

错误编号： d189e22a16644198b5d69a7b303fa4ec

错误信息： Unexpected character encountered while parsing value: <. Line 4, position 1.

===================================================

调用堆栈：

Server stack trace: 

   at Newtonsoft.Json.JsonTextReader.ParseValue(Char currentChar)

   at Newtonsoft.Json.JsonTextReader.ReadInternal()

   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadForType(JsonReader reader, Type t, JsonConverter propertyConverter)

   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType)

   at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)

   at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)

   at BAH.M4GQ.Kingdee.App.ServicePlugIn.PurchaseReturn.Delete.BeforeExecuteOperationTransaction(BeforeExecuteOperationTransaction e)

   at Kingdee.BOS.App.Core.PlugInProxy.OperationServicePlugInProxy.FireBeforeExecuteOperationTransaction(BeforeExecuteOperationTransaction e)

   at Kingdee.BOS.App.Core.AbstractOprerationService.DoExcete()

   at Kingdee.BOS.App.Core.AbstractOprerationService.Excute(Object[] ids)

   at Kingdee.BOS.App.Core.DeleteService.Delete(Context ctx, BusinessInfo info, Object[] Ids, OperateOption option, String operationNumber)

Exception rethrown at [0]: 

   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)

   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)

   at Kingdee.BOS.Contracts.IDeleteService.Delete(Context ctx, BusinessInfo info, Object[] Ids, OperateOption option, String operationNumber)

   at Kingdee.BOS.ServiceHelper.BusinessDataServiceHelper.Delete(Context ctx, BusinessInfo businessInfo, Object[] Ids, OperateOption option, String operationNumber)

   at Kingdee.BOS.Business.Bill.Operation.Delete.<DoListDelete>b__6(String[] ids, OperateOption option, List`1 paras)

这个自己写的插件扔出来的报错啊 BAH.M4GQ.Kingdee.App.ServicePlugIn