Errata: Section 2. Lemma 2.1. replace "the order of $\Delta$ is odd" by "the exponent $M$ is odd" Section 3. Step 1. The product runs over k = j modulo \delta Section 3. Step 2. The product runs over k = j modulo dp^a Section 3. page 926, line 10: The polynomial F(t) is incorrect. The one listed is the minimum polynomial of N(eta) rather than N(eta)^{X^2-1}. The correct polynomial is t^6 - 1306394247628*t^5 + 359348182378798*t^4 - 5041499042385662*t^3 + 2462693434453*t^2 - 299638410*t + 1 (or its reciprocal; this depends on choices of primitive roots ...etc) This time the polynomial G_1(t) DOES divide F(t^2) Section 4. Four lines before Table 4.3: the annihilator is *also* principal for l = 4297. Indeed, as we read a little further, the annihilator is generated by T + 2\zeta and by 4 in the ring W/8W[T]/(T^2 + 2T). Since we have (T + 2\zeta)*(T + 2 - 2\zeta) = 4 modulo (T^2 + 2T, 8), the annihilator is actually generated by T + 2\zeta. Therefore B_{\phi} is isomorphic to its dual. Main Table: the entry for l = 4049 is wrong. It is true that q = 23, but the degree is 22 rather than 11. Main Table: in the rightmost columns (both on page 935 and on page 936) the header should read "deg" rather than "h_l^+".