Hey there,
Since Flegy inserted the fixed .opdsub file to the new patch that reading the fxb's from your "fx" folder, i guess it what makes you crash.

Could be these reasons why it happens :
* You probably played with the "fx" folder effects and inserted random patch that replaced some of the fxb's that does not support 12xx KO Versions.
* You might have not installed all the patches correctly.

How to fix? :
* First to locate the problem by, make 1 test by renaming your "fx" folder to "fx2" so client won't be able to read effects from your fx and see if clients loads up.
^
|
Once you will notice it's fixed the problem, make sure you get from a friend the originally "fx" folder with all the inserted patches to that "fx" folder.
If you don't have friends Simply reninstall the client while firewall turned off and let the launcher do his job by installing all the patches properly.

Good luck.

Gilad pretty much explained it all, try that and it should be alright.

also you can send us log.klg file from your client