I have searched google and the forums. Nobody seems to have had this problem. (Makes me think it's something on my system.)
I'm running Ubuntu 13.04, with PoL 4.2.1 and Wine 1.5.29.
When I run World of Warcraft, regardless of whether I have previously checked the "Remember my username" box, I ALWAYS have to retype my username. Then, when I log into the server, I have to allow it to suggest a realm, then I have to change realms to get to the one my character is on.
All of this information is stored in <WoW Directory>/WTF/Config.wtf so I know it KNOWS it. I just don't know why it's not ACCESSING it.