CM7 SD card with Kindle app help

[hymeadowfield]

I have CM7 on SD card for my Nook color. It works great except for one thing. Lately when I open a Kindle book to read, then book mark it when I am done and then shut down the Nook, when I open Kindle app again it does not save my book. It downloads it again but it does open right where I left off. Only problem is, if there is no wi-fi access I can't get my book. This does not happen every time but has been happening more and more often. I don't recall this happening before this app upgraded a while ago. Is anyone else having this problem? What can I do to correct this so I don't have to keep downloading my books. Thanks.