Sometimes I have a problem that logging in on a certain character on an account, Aion client crashes as soon as logging the character in. Then I restart and just choose another character to log in. If the 2nd time it also crashes I use a 3d character to log in and it usually works. Sometimes I had to log in to a level 1 character that don't play, then go to Character section and choose one of the characters I wanted to play. The problem on that account disappeared in 2 or 3 weeks, but appeared on another account. If you tried all characters and all crash, try to go to character creation, and after that to your old character.