Created Unassigned: ValidatorCalloutExtender [27564]

I previously had multiple ValidatorCalloutExtenders targeting several RequiredFileValidators working correctly within my application.

I re-installed the latest version of the AjaxControlToolkit and now none of them are firing properly.

I have several other toolkit controls that work perfectly fine, but it appears the ValidatorCalloutExtendor is the only one not being displayed. I can also see the required field validator is working properly because the for will not submit as would be expected when the field is empty.

Here is a sample of one of the controls in question:

```
<asp:RequiredFieldValidator ID="RequiredLogin" runat="server" ErrorMessage="***Please enter a Login" ControlToValidate="txtUserLogin" ValidationGroup="UserLogin" CssClass="validationControl" Display="None"></asp:RequiredFieldValidator>
<ajax:ValidatorCalloutExtender ID="RequiredLogin_ValidatorCalloutExtender" runat="server" Enabled="True" TargetControlID="RequiredLogin" >
</ajax:ValidatorCalloutExtender>
```

I have looked across the internet and am at a loss as to why this is happening. Any help you can provide would be greatly appreciated.

Thanks!

Sean