The player database Argonath server uses on the T4 client is from 26th January, Firday just before the first test. It may be possible that you did not have an account at the time, so you would basically have to register a new account for the purpose of testing.
As for the T3, could you please check what does it say in your
Grand Theft Auto 4/IVMP/settings.xml
Do you have anything written in the <chatfont> line?
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