Google Talk Plugin error creating an account

Hi troubleshooters,
I installed the GTalk plugin in the computer and I created an account in Gmail. I followed all the instruction to create an account. After creating when I try to login I am getting a weird error message, this makes me irritating. Why I get this annoying error message? I am damn sure that username and password is correct. How do I fix the error? Please support me with some idea. Thanks.

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Username and password do not match. (You provided…)
OK
