@Nekrosys More info plz!! without info i can't tell u whats wrong. even with info its hard to tell. Give me at least the Walker version, if u have Loopback or not, tunnel or not, Firewall (and what kind off). Virus scanner. what protocol u are using and what server u wanna enter.
i know one thing!! u are close to enter it

because u logged in already u only can't enter world (looks like walker version or protocol version).
Greets Sillicon