Sounds as if it that page doesn't have a reference to mmUser. Do you have this toward the top (assuming C#)?

using OakLeaf.MM.Main.Security;

>C:\Inetpub\wwwroot\mmJumpStart\Admin\ControlSecurityConfiguration.aspx.cs(28): The type or namespace name
'mmUser' could not be found (are you missing a using directive or an assembly reference?)
>
>This is what I get in a rebuild.