Cache time is set to 0...I have disabled AJAX on the host settings and this seems to make a difference, i.e. it seems to work once again. Here is the code I use to launch the next screen...
Protected Sub grdCourseDates_RowEditing(ByVal sender As System.Object, ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles grdCourseDates.RowEditing
Dim ctlEventTypes As New EventTypeDetailsController
Dim infEventType As EventTypeDetailsInfo = ctlEventTypes.GetEventTypeDetails(Request.Params("evt"))
v13wstat3("eventtypename") = infEventType.EventName
Dim valEventID As Integer = Me.grdCourseDates.DataKeys(e.NewEditIndex).Value
Response.Redirect(EditUrl("", "", "EditScheduledEventDetails", "eventedit=" & valEventID, "evtype=" & CStr(infEventType.EventTypeID)))