HI there

I have a web project that shows the message box on a button_click event

Me.MsgBox1.Show("Atención", Session("Observaciones"), Nothing, New EO.Web.MsgBoxButton("Aceptar", Nothing, "acepta"), New EO.Web.MsgBoxButton("Cancelar", Nothing, "cancela"))

and on the msgbox button click event i got:

Private Sub MsgBox1_ButtonClick1(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.CommandEventArgs) Handles MsgBox1.ButtonClick
Try
If e.CommandName = "acepta" Then

If Session("borrar") = True Then
Borrar() 'erase the current data function
Else
Registra() 'register the current data function
End If

Button1_Click(sender, e) 'code to fill a datagrid
Else

End If
Catch ex As Exception

End Try

Session("borrar") = False
End Sub

Well my problem is the next one: when i get the msgbox showed up, i click the button "Aceptar" and i get these kind of errors on my IE8 :

Mensaje: 'EO834.f.aki().afc' es nulo o no es un objeto ('EO834.f.aki().afc' is null or is not an object)
Línea: 6
Carácter: 14959
Código: 0
URI: http://siap/WebSiap/eo_web.ashx?id=b9cb25f5-3e8d-4329-b71d-2a73b6d2df96


Mensaje: 'null' es nulo o no es un objeto
Línea: 6
Carácter: 25042
Código: 0
URI: http://siap/WebSiap/eo_web.ashx?id=174de4b0-2005-45f7-b1c3-95951d5b2002


Mensaje: 'EO834.f.aki().afc' es nulo o no es un objeto
Línea: 6
Carácter: 14959
Código: 0
URI: http://siap/WebSiap/eo_web.ashx?id=b9cb25f5-3e8d-4329-b71d-2a73b6d2df96


Sometimes the code works perfect but sometimes i get those error messages.
English is not my primary language hope you can understand my problem

Help :(