It seems that there is some design flaw on the the new curved casing on the 4th gen. I've been reading through different posts, and this seems to be a recurring problem and needs to be addressed by Apple. After a lot of use, the board/clickwheel loosens up and creates some form of unstable contact. A solution I found is to add a firm backing to it. I did this by inserting a piece of thin plastic (a thin old credit card would do) between the board and the aluminum casing on the bottom end of the iPod. I tried this with 2 of my iPods and it worked. Of course you need to take out the bottom plastic cover and the aluminum connector support with the 2 screws first. Hope this works for you guys. GOOD LUCK!