remember to run update "LineageII.exe" not "L2.exe".
If that doesent work, then try the usually "delete the gameguard folder inside your system folder" and runn full check.
I have not tried yet, but EVERY time some change is made in the Lineage software, my firewall silently blocks access to it. I have to manually re-grant 'program permissions' to all the Lineage-related programs, including GameGuard. I bet many of the folks still having problems need to do this too.