the issue is with the single OR gate(s) at the end
What is the value of R for that circuit. It is unlikely that your problem is there. To check just disconnect it.
the circle was in lieu of using yet another colour, so it was just to indicate which pin was for the 'SUM' output for the LED.
So not a resistor then?
I would draw a circuit like this:-
Then I would add the pin numbers and IC number on the symbols.
Your final carry out seems to be looped back into the beginning? There should be an LED on the carry out of the last stage.