I've not tried this with sybase, but it should be common to all SQL systems.
Make sure your "parametername" in the Parameters.Add statement is identical to that used in your SQL Text:
string CommandText = "select name, password from dtident where name=@token";
cmd.Parameters.AddWithValue("@token",value);
You could use Parameters.Add but that is more complex:
cmd.Parameters.Add("@token",DbType.Integer).Value = value;