Overdrive Media Console is your problem (also see my previous post). Having it installed means it will automatically make itself the default for most of your ereading downloads. Still, if you side load files onto your device using either a flash drive or the mini USB cord, instead of opening them through Overdrive, you can read them on the eink screen. Just remember to open them on your pc first.
Overdrive became so problematic for me that I uninstallled it.