not able to make new add on layout feature working

Hi there. We are using SBO 8.81 PL09 and have make an addon with UDO's. Triying to print the udo objects thorw crystal report and doing everything explained here:

[http://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/26720%3Fpage%3Dlast%26x-order%3Ddate%26x-showcontent%3Doff]

System gives us an error:

"Input string was not in a correct format". Problem arises when executing:

 Private Sub SBO_Application_LayoutKeyEvent(ByRef eventInfo As SAPbouiCOM.LayoutKeyInfo, ByRef BubbleEvent As Boolean) Handles SBO_Application.LayoutKeyEvent
        Dim oForm As SAPbouiCOM.Form = SBO_Application.Forms.Item(eventInfo.FormUID)
        Dim oEdit As SAPbouiCOM.EditText = oForm.Items.Item("4").Specific
        If eventInfo.BeforeAction = true Then
            eventInfo.LayoutKey = oEdit.Value
        End If

We are stuck with this matter. Anyone have a clue?

Thanks so much!