It was panned by almost all the critics, and it's possible that the massive marketing campaign was counterproductive. All those interviews in all the papers, former pirate DJs turning up on TV and radio, soundtrack albums being advertised on the cinemas' web sites etc may have put existing Curtis fans off by making the film seem too anoraky.
It's nowhere near as bad a film as some of the reviews suggested. The cinematography is gorgeous, the music is great (if nothing like what was really played on pirate radio at the time) and the cast are excellent (particularly Philip Seymour Hoffman). But it's not in the same league as some of Curtis's earlier films - and just not as funny.