its saying your user name password invalid where as i ve already logged in

hi there,
i ve signed in as mithunlaltu1
its welcomes me
but when i am in download it says cant connect server and reconnect
after sometime it says in valid user name .... how to come out of this problem .
iwant to download the song Rabindra\Prashun + Kumar Sanu\03 - Prasun Mukherjee - Ektuku Chhowa Lage.mp3
but it is not permitting me
so if any one have please mail me to
mithun.laltu1@gmail.com
hey thanx in advance
mithun