Red Octane has confirmed via its customer support team that unfortunately there is a batch of Guitar Hero II X Plorer controllers for the Xbox 360 with a faulty whammy bar. The problem causes whammy bar movements to either not be registered withint the game, or for there to be a slight delay before you whammy bar movements are represented on screen.
Red Octane has promised that unsatisfied customers can exchange their controllers at their place of purchase, or if purchased via their online store, can submit an RMA request and have the faulty controller exchanged.
The problem is isolated to two specific models of the controller, the numbers of which are 95065 and 95055.
However all is not as bad as it seems as the guys at allaboutthegames.net have discovered a remedy to this problem which is as simple as loosening two screws and which does not void your warranty. Carefully follow the simple instructions and click on each of the images in order to view larger high resolution versions.