I see many players have problems with Facebook login when they want to play A.V.A so here's simple instructions how you can get your A.V.A username and password for your Facebook A.V.A account:
1. go to main A.V.A page http://ava.ijji.com/index.nhn
and click on "jji Sign In"
2. click Forgot your ID/Password?
3. under "Find User ID" write your Facebook email and click "Send user ID to E-mail"
4. go to your email where you should get your A.V.A username. For my Facebook A.V:A account it was like this: fq_[numbers]
5. repeat steps 1 and 2 and then under "Find Password" write your A.V.A username and click "Send Password info to E-mail". You should be able to choose your password.
This way you'll get yourself username and password for your Facebook A.V.A account so you can login normal way instead of Facebook login.