  We prove that some ergodic linear automorphisms of $\T^N$ are stably ergodic,
i.e. any small perturbation remains ergodic. The class of linear automorphisms
we deal with includes all non-Anosov ergodic automorphisms when N=4 and so, as
a corollary, we get that every ergodic linear automorphism of $\T^N$ is stably
ergodic when $N\leq 5$.
