Conversion error from DECF34 to byte[]

When there is a RFC call to function module from SAP we are getting error from dot net code as below

 When there is a function call via RFC we are getting below error

ERROR IN Y_BC_IXOS_CHECK_LINE_ITEMS FUNCTION : FIELD HIST_TAX_FACTOR1 of STRUCTURE BSEG (GETTER): cannot convert DECF34 into Byte[]

Is there a way where we can resolve the Conversion error from DECF34 to byte[]?

Below is the code where there is error:-

    Public Function CheckLineItemsNew(ByVal strCompanyCode As String, ByVal DataList As Hashtable, ByRef ErrorList As DataTable) As String

        Dim strMessage As String = ""

        Dim strFunction As String = GetObjectNameFromConfig("Y_BC_IXOS_CHECK_LINE_ITEMS")

        Dim DataTable As IRfcTable

        Dim ErrorTable As IRfcTable

        Dim DataIn As IRfcStructure

        Dim i As Integer

        ErrorList = New DataTable

        If DataList.Count = 0 Then

            strMessage = "The input list 'DataList' is empty."

            Return strMessage

        End If

        Try

            WriteLog("Start CheckLineItemsNew")

            'Set Function

            Dim MyFunction As IRfcFunction = SapDestination.Repository.CreateFunction(strFunction)

            'Set import values

            MyFunction.SetValue("IW_BUKRS", strCompanyCode.ToUpper)

            'Set Table

            Dim metadata As RfcStructureMetadata = SapDestination.Repository.GetStructureMetadata("BSEG")

            DataTable = MyFunction.GetTable("IWT_LINEITEMS")

            'Add data

            For i = 1 To DataList.Count

                DataIn = metadata.CreateStructure()

                If DataList.Item(i).ContainsKey("HKONT") Then

                    DataIn.SetValue("HKONT", DataList.Item(i).Item("HKONT").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("WRBTR") Then

                    DataIn.SetValue("WRBTR", DataList.Item(i).Item("WRBTR").ToString.ToUpper)

                End If

                'If DataList.Item(i).ContainsKey("MWSKZ") Then

                '    DataIn.SetValue("MWSKZ", DataList.Item(i).Item("MWSKZ").ToString.ToUpper)

                'End If

                If DataList.Item(i).ContainsKey("KOSTL") Then

                    DataIn.SetValue("KOSTL", DataList.Item(i).Item("KOSTL").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("AUFNR") Then

                    DataIn.SetValue("AUFNR", DataList.Item(i).Item("AUFNR").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("PROJK") Then

                    DataIn.SetValue("PROJK", DataList.Item(i).Item("PROJK").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("SGTXT") Then

                    DataIn.SetValue("SGTXT", DataList.Item(i).Item("SGTXT").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("VBUND") Then

                    DataIn.SetValue("VBUND", DataList.Item(i).Item("VBUND").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("XREF3") Then

                    DataIn.SetValue("XREF3", DataList.Item(i).Item("XREF3").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("BUKRS") Then

                    DataIn.SetValue("BUKRS", DataList.Item(i).Item("BUKRS").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("MATNR") Then

                    DataIn.SetValue("MATNR", DataList.Item(i).Item("MATNR").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("PRCTR") Then

                    DataIn.SetValue("PRCTR", DataList.Item(i).Item("PRCTR").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("BEWAR") Then

                    DataIn.SetValue("BEWAR", DataList.Item(i).Item("BEWAR").ToString.ToUpper)

                End If

                'Only for France GSBER and ZUONR

                If DataList.Item(i).ContainsKey("GSBER") Then

                    DataIn.SetValue("GSBER", DataList.Item(i).Item("GSBER").ToString.ToUpper)

                End If

                If DataList.Item(i).ContainsKey("ZUONR") Then

                    DataIn.SetValue("ZUONR", DataList.Item(i).Item("ZUONR").ToString.ToUpper)

                End If

                DataTable.Append(DataIn)

                DataIn = Nothing

            Next

            'Call function

            MyFunction.Invoke(SapDestination)

            'Get error table

            ErrorTable = MyFunction.GetTable("EWT_RETURN")

            'Convert datatable

            strMessage = ConvertToDataTable(ErrorTable, "EWT_RETURN", ErrorList)

        Catch ex As Exception

            strMessage = ex.Message

            WriteLog("ERROR CheckLineItemsNew : " & strMessage)

        End Try

        Return strMessage

    End Function