Your are facing a classic C++ problem.

Replace following function declaration:
friend ostream& operator << (ostream&,const Derived<T>&);

to

friend ostream& operator << <> (ostream&,const Derived<T>&);

and also replace
friend istream& operator >> (istream&,Derived<T>&);

to

friend istream& operator >> <>(istream&,Derived<T>&);

Note: Only make change in function declaration and not in function definition.

The problem is that you need to tell the compiler that the declared friend function is a template.

Let me know if this works or if you face any problem.