You could:
1) Be connecting into an older server, in which case running "Update Everything" should fix it;
2) Have installed the game again, but chosen the same screen name, so when the game generates the random password for the screen name you selected, since it does not match the old one, it can't connect, in which case, you just PM Kralik with you GCCG username and he'll send you your password, which then you input into the "Password" .txt file the system has generated into the .gccg folder