As above, torque that hub nut up sharpish! Did you make sure both cylinders and handbrake mech were all free and working properly? If they're sticking at all it may have cooked the friction material, which can cause squealing. Also, if they're eicher shoes from euros or something similarly cheap and nasty then they can do that if not bedded in carefully.
Edit: also, try the braking section next time.
Edit: also, try the braking section next time.
