Validation of viewstate MAC failed... Help!

[Tbaseflug]

I have the following ajaxevent tied to a scriptmanager - works without issue on every other page - on this page, whcn I click on the span targeted in the below, I get the viewstate error - I even have eventvalidation, etc. set to false in my page


<ext:ScriptManagerID="ScriptManager2"runat="server ">
<CustomAjaxEvents>
<ext:AjaxEventTarget="spnDetailReport"OnEvent="rep ortCommandClick"IsUpload="true">
<ExtraParams>
<ext:ParameterName="intID"Value="document.getEleme ntById('ddlPendingCharges').value"
Mode="Raw"/>
<ext:ParameterName="reportName"Value="Pending Charge Final Report"Mode="Value"/>
<ext:ParameterName="format"Value="PDF"Mode="Valu e"/>
</ExtraParams>
</ext:AjaxEvent>
</CustomAjaxEvents>
</ext:ScriptManager>

and have these in the page attributes:
EnableViewState="false" EnableViewStateMac="false"
EnableEventValidation="false"

[Tbaseflug]

This occurs in a page tested in a tab panel - when I place

EnableViewState="false"EnableViewStateMac="false"
EnableEventValidation="false"

In the tabpanel/container page - the error goes away but then the ajaxevent stops working?