First make sure Java is installed, enabled, and up to date.
Then check and make sure that your antivirus and or firewall is not blocking Java from connecting to the internet.
Once that's done, check and see if your connection works now, (pending that you had to make changes and or updates).
If you still can't connect, continue reading…
In IceChat, right click on the entry (that you should have), for Furtopia and select “Edit Server…” (If you are using the default setup, the Furtopia entry should be in the right pane, under the “Favorite Servers” tab.)
Once in the server settings, under “Basic”, check the entries for “Server Name:” and “Server Port:”
If Server Name says anything other than: irc.furtopia.org
And if Server Port is anything other than: 6007
Then you will not be able to connect, make absolutely sure that everything is typed 100% verbatim to what I typed.
If your entries differ in any way, make the necessary corrections and see if that fixes the problem, if it does not fix the problem, or if your entries are correct to begin with.
Then it would help to know what other settings you have, such as are you using any Proxy or BNC settings in IceChat, if you have any auto-defines, or any auto-join settings, etc. that may be conflicting with how your client connects.