Compare your code against the sample code below. It is possible you might have some properties on the View configured improperly:

<asp:MultiView ID="mv" runat="server">
    <asp:View ID="vw1" runat="server">
    </asp:View>

     <asp:View ID="vw2" runat="server">
     </asp:View>
</asp:MultiView>

To set the active view, the code should be as follows:

'Set the "vw1" View to be visible and active:
Me.mv.SetActiveView(Me.vw1)

If you continue to have problems, please post your code to help further.