I'm honestly not sure if this is anything more than a coincidence, but you might want to try it. Since the maintenance, I've been getting hit with 3102 after D/Cing. It appears that if I log onto a character on the other server farm (i.e. for you it would be a JP server) and logout, then I can log back in on my original character.

For example, I'm on Diabolos, an NA server. During beta, I made a character on Ultima (JP). More often than not, if I get D/C'd (aka. error 90000) on my Diabolos character and then get slapped with a seemingly perpetual error 3102, logging in and out on my Ultima character seems to let me back in Diabolos.

Again, it could be purely coincidence, and it surely isn't a permanent fix. However, it might help you play some until a fix is found.