problems occured and solved in 02-04-2012

1: repeating the process

solved by using If(verifier==null) before the asyn() function.

2: application value becoming null

then used the code with
 _oauth.Token = Application["auth_token"].ToString();
            _oauth.TokenSecret = Application["auth_tokensecret"].ToString();
            _oauth.Verifier = Application["auth_verifier"].ToString();
          
3: some times system showing error the verifier doesnot match.
sol: do the refresh , rebuild it and run.