Thanks to some of our helpful forum members (gali, He Man, Ca1n) who have kept the executable files from the previous client version, you can revert your executable from:
http://www29.zippyshare.com/v/68455088/file.html From gali
http://rapidshare.com/files/291998867/eXes.rar From He-Man
http://rapidshare.de/files/48508137/FOnline.rar.html From Ca1n
More info about the whole issue on the forum.
We will try to synchronise the updates as soon as possible, so you can keep playing after updating the client using the official updater.
Thank you for your understanding.