I have an E250 and have digital books on it from Overdrive.com. These books are in WMA format and utilize digital rights management. The books play just fine under the original Sandisk software, but do not play at all when I use Rockbox. I can locate the book files, but when I hit enter on it the display says, "unknown artist, unknown album, 4-no file". If I select it a second time, the no file message is replaced with " ?Kbps APE The time display sits at zero. As a guess it appears that Rockbox is not allowing the digital rights management to operate correctly. Help?