Class will compile for Tests/Console but not in Asp.net application

public interface IVisitorsLogController
{
    List<VisitorsLog> GetVisitorsLog();
    int GetUniqueSubscribersCount();
    int GetVisitorsCount();
    string GetVisitorsSummary();
}

private IVisitorsLogController ctl;

protected int GetUniqueMembersCount()
{
    ctl = new VisitorsLogController();
    return ctl.GetUniqueSubscribersCount();
}

protected static int GetVisitorsCount()
{
    return VisitorsLogController.Instance.GetVisitorsCount(DateTime.Today);
}

ctl = VisitorsLogController.Instance;