Hey!
Firstly, lets make sure your mute switch is off. On updating to iOS 4.2, the screen rotation lock changed to a mute switch. Check this is not on!
Otherwise, If other audio is not working, then contact Amazon as it is the kindle app which has the malfunction. You can find help here: [Kindle for iOS help|http://www.amazon.com/gp/help/customer/display.html/ref=hp
navbox_topkindleiphonei?nodeId=200298460] and you can contact support at this site: [Contact Kindle Support|http://www.amazon.com/gp/help/customer/display.html/ref=hp
iplandreccont?nodeId=200212360]
Hope this helps!
< Edited by Host >