a form tag:
<form id="theform" runat="server">
Because I have several user controls on the page each of which has
separate form controls and functionality I have added the form tag on the
aspx page and added my user controls within the tags. This way, all the
different form controls and logic share the same server form control.
The error points to the rendered form tag which is.
<form name="theform" method="post" action="test.aspx" id="theform">
I've seen some similar problems in my search but most refer to doPostBack