Hey, welcome to the group. Hope you enjoy it here.
As to your dilemma, I'm directing you to this recent thread for some possible solutions:
Audio books - info?
Long story short, Android and WMA don't mix. My suggestion is to use an inexpensive MP3 player for WMA audiobooks from the library. That's what I do. Most of them will handle the major audiobook formats - MP3, WMA, Audible.