Simply use CLEAN ncsoft download full 2.0 installer clients.
You will SURE have no problem
ONLY clean and fully updated 2.0.0.3 clients (preferable NA (north america)) are accepted.
Most people that played other P.server before WOS may have some problem since some p.servers patch let some "trash" on the game folder that may interfere in client behavior.
Please read and follow what iam saying and you will not have problems anymore with any servers.