Call to Session.CreateSQLQuery ExecuteUpdate fails in NHibernate

using(var tx = Session.BeginTransaction())  {
    Session
        .CreateSQLQuery("exec dbo.spSyncData")
        .ExecuteUpdate();
    tx.Commit();
}

return Session.CreateCriteria(typeof(MyData))
    .Add(Restrictions.Eq("Status", Status.Waiting))
    .List<MyData>();