We listen to audiobooks from overdrive on a usb stick. In the beginning, there was a bar across our screen where we could quickly fast forward or backup books. We were able to fine tune to the exact place we wanted. Now it appears to be gone. we Can fast forward chapters,but do not have the ability to fine tune spots using this bar across the screen feature. Is This a problem with the brand of memory stick, the software version of overdrive, or a flaw in our system?