diff --git a/Contabilidad/RegPrePolizaS.aspx b/Contabilidad/RegPrePolizaS.aspx
index 4ba12dac4..fa0bebecb 100644
--- a/Contabilidad/RegPrePolizaS.aspx
+++ b/Contabilidad/RegPrePolizaS.aspx
@@ -224,9 +224,11 @@
                                                 </th>
                                                 <th>
                                                     <asp:TextBox ID="TxtAbono" runat="server" Width="76px" Height="24px" CssClass="txtabono"></asp:TextBox>
+                                                    <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="TxtAbono" Display="None"  ErrorMessage="<b><span style='text-decoration: underline'>ERROR:</span></b><br />El campo <b>''Abono''</b> es necesario." ValidationGroup="ValidarAbono"></asp:RequiredFieldValidator>
+                                                    <ajax:ValidatorCalloutExtender ID="ValidatorCalloutExtender3" runat="server" HighlightCssClass="vco" TargetControlID="RequiredFieldValidator2" Width="30px" PopupPosition="BottomLeft"></ajax:ValidatorCalloutExtender>
                                                 </th>
                                                 <th align="center">
-                                                    <asp:LinkButton ID="LbAgregar" runat="server" CssClass="Texto" Enabled="true" Text="Agregar"></asp:LinkButton>
+                                                    <asp:LinkButton ID="LbAgregar" runat="server" CssClass="Texto" Enabled="true" Text="Agregar" ValidationGroup="ValidarAbono"></asp:LinkButton>
                                                     <asp:LinkButton ID="LbCancelarEdicion" runat="server" Visible="false" CssClass="Texto" Enabled="true" Text="Cancelar"></asp:LinkButton>
                                                 </th>
                                                 <th runat="server" visible="false" id="nomostrar"></th>