I played in a lot of server's, l2j & l2 off. I have NOD32 Smart Security 4 Installed and the only warning i got its the themida thing like in most of the patched systems around, even some of microsoft files are marked as trojan horses from antiviruses.
This server has the best interest to provide the best security for the players so they have their own "home" to forget real life problems and have some fun. If they wanted to spread a virus or something they wouldn't even think about working so many hours on that server.
Join People this is a very nice server and if you have any problem you can contact the server's Staff for help.
P.S: My english might suck but at least you get the point.