First of all update your client
Then go to http://vitreous.4shared.com and download "l2encdec_281.zip" .
Extract all files from "l2encdec_281.zip" to the system folder of LineageII (C:/Program Files/LineageII/system)
Run patcher.exe ! An MS-DOS window will appear and let it complete.
* Then Go , Start -> Run and type cmd and try to find the system folder from there. (For ex. You will start by typing "cd prog*" and you will get to "Program Files" , then "cd Lineage 2" and "cd system".)
* Ok now you are in the system folder from cmd . Type "l2encdec -s l2.ini" (without") . It will translate the "l2.ini" to a file called "dec-l2.ini". Right click on it and then open it with Notepad.
Find the row "serveraddr=" and put your External IP(www.whatismyip.com)or your Internal IP (Your net IP or 127.0.0.1) and save it.
* From the system folder delete l2.ini and go back to (cmd) and type l2encdec -h 413 dec-l2.ini . It will change dec-l2.ini into a new file called enc-dec-l2.ini . Then just rename enc-dec-l2.ini to l2.ini .