Hah! I didn't think of it in that context; i.e., it's the PC not charging the Reader instead of the Reader not accepting juice. So given that, then you should be able to charge it using a stand-alone *dumb* charger. Considering that Patricia reports charging it via a solar USB charger, then the el-cheapo $5 USB charger will work.
Thanks Nerys, I guess sometimes I need to think outside of the box (though this time it was inside the box!
).