二开的单据，新增单据保存时错误

二开的单据，新增单据保存时错误如下：（KEY是什么？）
Value cannot be null.
Parameter name: key

[{"operation":"ff31f1ff-2b96-42b0-aee7-2c052a84082e.MBIClick.tbSplitSave"}]
发生时间：09:32:06
错误来源： Kingdee.BOS.ServiceHelper
错误信息：Value cannot be null.
Parameter name: key
===================================================
调用堆栈：
Server stack trace:
at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
at Kingdee.BOS.App.Core.MetadataXmlReader.LoadFromCache(String id, Boolean bGetBaseObject, Int32 modelTypeId)
at Kingdee.BOS.App.Core.MetadataXmlReader.LoadFromIISCache(String id, Boolean bGetBaseObject, Int32 modelTypeId)
at Kingdee.BOS.App.Core.MetadataXmlReader.Load(String id, Boolean runtime, Boolean loadEmbedRefObject, Boolean getBaseObject, Int32 modeltypeId, Boolean isLoadSubObject)
at Kingdee.BOS.App.Core.MetaDataService.Load(Context ctx, String id, String layoutViewId, Boolean bRuntime)
at Kingdee.BOS.App.Core.MetaDataService.Load(Context ctx, String id, Boolean bRuntime)
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.IMetaDataService.Load(Context ctx, String id, Boolean bRuntime)
at Kingdee.K3.SCM.App.Sal.ServicePlugIn.SaleOrder.Save.OnAddValidators(AddValidatorsEventArgs e)
at Kingdee.BOS.App.Core.PlugInProxy.OperationServicePlugInProxy.FireOnAddValidators(AddValidatorsEventArgs e)
at Kingdee.BOS.App.Core.AbstractOprerationService.TryValidate()
at Kingdee.BOS.App.Core.AbstractOprerationService.Validate()
at Kingdee.BOS.App.Core.AbstractSave.Validate()
at Kingdee.BOS.App.Core.AbstractOprerationService.DoExcete()
at Kingdee.BOS.App.Core.AbstractOprerationService.Excute(DynamicObject[] dataEntities)
at Kingdee.BOS.App.Core.SaveService.Save(Context ctx, BusinessInfo info, DynamicObject[] dataEntities, OperateOption option, String operationNumber)
Exception rethrown at [1]:
at Kingdee.BOS.ServiceHelper.BusinessDataServiceHelper.Save(Context ctx, BusinessInfo businessInfo, DynamicObject dataObject, OperateOption option, String operationNumber)
at Kingdee.BOS.Model.Bill.BillModel.Save(OperateOption option)
at Kingdee.BOS.Business.Bill.Operation.Save.ExecuteBillOperation(OperateOption option)
at Kingdee.BOS.Core.DynamicForm.AbstractDynamicFormOperation.Operation(CallBackWfAfterOperation callbackwf, IOperationResult result)
at Kingdee.BOS.Core.DynamicForm.AbstractDynamicFormOperation.Execute(InvokeFormOperation4WfParam param, CallBackWfAfterOperation callbackwf)
at Kingdee.BOS.Web.DynamicForm.AbstractDynamicWebFormView.InvokeFormOperation(String operationNumber)
at Kingdee.BOS.Business.DynamicForm.BusinessService.ExcuteOperation.DoAction(FormBusinessServiceArgs e)
at Kingdee.BOS.Core.DynamicForm.FormBusinessServiceUtil.InvokeServices(IDynamicFormView view, Object source, IEnumerable`1 services, Int32 actionType, String activeEntity, DynamicObject activeRow, Int32 rowIndex)
at Kingdee.BOS.Web.DynamicForm.BusinessServiceCaller.InvokeFormBusiness(IDynamicFormView view, Object source, List`1 formBusinessServices, Int32 actionType, String entityKey, Int32 row)
at Kingdee.BOS.Web.DynamicForm.DynamicWebFormView.BarItemClick(String parentKey, String barItemKey, BarDataManager bar, Int32 bartype)
at Kingdee.BOS.Web.DynamicForm.DynamicWebFormView.MainBarItemClick(String barItemKey)
at Kingdee.BOS.Web.DynamicForm.DynamicWebFormController.MainBarItemClick(String itemKey, JSONArray postDatas)
错误数据： System.Collections.ListDictionaryInternal