Thanks for the replies. I will search again for WPA or WPA2 issues here on the Kobo forum, thank you.
Yes, my WPA2 password is strictly alphanumeric, 32 characters long. I cringe to think that any new-on-the-market WiFi-connected device would barf on a 32 character password in 2014, but if a shorter password would actually solve my problems, then I'd definitely consider it as a temporary solution. I'll leave that as a last resort -- many other network devices get disrupted with each password change!
It's not a crazy theory though, so thank you!
And I'll let you all know if Kobo Customer Service comes through with anything.