计算定义公式的值并填写到指定列，出错

首先，我想做的是在采购订单下推成采购收料单时，把仓库的值自动填写上指定的值，我在单据转换中使用表单服务策略，定义了 计算定义公式的值并填写到指定列， FStockID ='待检-供应商来料待检' （可能是值的属性不匹配，不知道应该怎样写呢） 在下推单时，就报错。
The value "Microsoft.Scripting.Interpreter.InterpretedFrameInfo" is not of type "System.String" and cannot be used in this generic collection.
Parameter name: key
[{"operation":"BOS_ConvertOpForm.BClick.FBTNOK."}]
发生时间：16:15:00
错误来源： mscorlib
错误信息：The value "Microsoft.Scripting.Interpreter.InterpretedFrameInfo" is not of type "System.String" and cannot be used in this generic collection.
Parameter name: key
===================================================
调用堆栈：
Server stack trace:
at System.ThrowHelper.ThrowWrongKeyTypeArgumentException(Object key, Type targetType)
at System.Collections.Generic.Dictionary`2.System.Collections.IDictionary.set_Item(Object key, Object value)
at Microsoft.Scripting.Interpreter.Interpreter.HandleException(InterpretedFrame frame, Exception exception)
at Microsoft.Scripting.Interpreter.Interpreter.Run(InterpretedFrame frame)
at Microsoft.Scripting.Interpreter.LightLambda.Run2[T0,T1,TRet](T0 arg0, T1 arg1)
at IronPython.Compiler.PythonScriptCode.RunWorker(CodeContext ctx)
at IronPython.Compiler.RuntimeScriptCode.InvokeTarget(Scope scope)
at Kingdee.BOS.Scripting.PyExpressionEvaluator.Run(Expression expression, ExpressionContext context)
at Kingdee.BOS.App.Core.Convertible.BusinessService.Calculate.DoAction(PushBusinessServiceArgs e)
at Kingdee.BOS.App.Core.Convertible.ExecuteFormBusinessAction.ExecuteFormBusinessService(IDynamicFormModel model, FormBusinessService service, IPushFormBusinessService executeService)
at Kingdee.BOS.App.Core.Convertible.ExecuteFormBusinessAction.Do()
at Kingdee.BOS.Core.BusinessPolicyModel.BusinessPolicyEngine.Do(OperateOption context)
at Kingdee.BOS.App.Core.Convertible.ConvertEngine.OnCreating(PushArgs pushArgs, OperateOption option)
at Kingdee.BOS.App.Core.ConvertService.Push(Context ctx, PushArgs serviceArgs, OperateOption option, Boolean validPermission)
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.IConvertService.Push(Context ctx, PushArgs serviceArgs, OperateOption option, Boolean validPermission)
at Kingdee.BOS.ServiceHelper.ConvertServiceHelper.Push(Context ctx, PushArgs serviceArgs, OperateOption option)
at Kingdee.BOS.Business.Bill.Operation.Push.DoPush(OpFormReturnInfo retInfo, ListSelectedRow[] thisViewSelectedRows, ListSelectedRow[] selectedRows)
at Kingdee.BOS.Web.DynamicForm.DynamicWebFormView.FormClosedCallBack(String id, Boolean isSyncCall)
at Kingdee.BOS.Web.DynamicForm.AbstractDynamicWebFormView.CloseWindow()
at Kingdee.BOS.Web.DynamicForm.AbstractDynamicWebFormView.OnClose()
at Kingdee.BOS.Business.DynamicForm.ConvertPlugIn.ConvertOpFormEdit.ButtonClick(ButtonClickEventArgs e)
at Kingdee.BOS.Core.DynamicForm.PlugIn.DynamicFormViewPlugInProxy.FireButtonClick(ButtonClickEventArgs e)
at Kingdee.BOS.Web.DynamicForm.DynamicWebFormView.ButtonClick(String key, String menuKey)
at Kingdee.BOS.Web.DynamicForm.DynamicWebFormController.ButtonClick(String buttonKey, String menuKey, JSONArray postDatas)
错误数据： System.Collections.ListDictionaryInternal