In Example 3.4 the expression for \Phi(t) should be f(t^4)((1/(1-t)^2 - 3/2(1-t) + 1/2) + ... = f(t^4)((t+t^2)/(2(1-t)^2)) + ... The subsequent expression for \Phi(t) and its expansion on lines -2 and -3 of the paper appear to be correct. I thank Dave Benson for pointing this out. April 2005