Erro

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(
                    R.layout.fragment_register_new_user, container, false);
            Button goToLogin = (Button) rootView.findViewById(R.id.doLogin);
            Button createAccount = (Button) rootView
                    .findViewById(R.id.login_submit);
            final EditText username = (EditText) rootView
                    .findViewById(R.id.username);
            final EditText password = (EditText) rootView
                    .findViewById(R.id.password);
            final EditText confirmPass = (EditText) rootView
                    .findViewById(R.id.password_confirm);
            final EditText email = (EditText) rootView.findViewById(R.id.email);

            goToLogin.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    Intent i = new Intent(getActivity(), MainActivity.class);
                    startActivity(i);

                }
            });

            createAccount.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub

                    ParseUser parseUser = new ParseUser();
                    parseUser.setUsername(username.toString());
                    parseUser.setPassword(password.toString());
                    parseUser.setEmail(email.toString());
                    parseUser.put("confirmPass", confirmPass.toString());

                    parseUser.signUpInBackground(new SignUpCallback() {

                        @Override
                        public void done(ParseException e) {
                            // TODO Auto-generated method stub

                            if (e == null) {

                                Toast.makeText(
                                        getActivity().getApplicationContext(),
                                        "Usuário cadastrado com sucesso",
                                        Toast.LENGTH_SHORT).show();

                            } else {

                                Toast.makeText(
                                        getActivity().getApplicationContext(),
                                        "Ops! Algo deu errado. Tente novamente!",
                                        Toast.LENGTH_SHORT).show();

                            }

                        }
                    });

                }
            });
            return rootView;
        }