For a Gracia Epilogue client you will need to download In-Game walker 2.17b and make sure Disable GameGuard is checked when starting lineage2 to use the L2WBypass work around. It is probably a better idea to also simulate GameGuard when disabling GameGuard from L2Walker.
There is also a newer version of L2WBypass which allows you to change the IP address you forward to that I released earlier this week. This can allow you to use in-game on some private servers by changing the IP address in config.ini.
Here is the download link: