I hope I understand your problem. The screws that screw directly thru the vertical uprights to the horizontal short tube that connects to the rear of the RV.
Normally, there is a press in winged nut that will go into the horizontal tube in one direction but cannot be pulled back out. You may have accidentally pushed that nut affair deeper into the tube so that the existing 1/4 x 20 screw (bolt) can't reach it. I'd suggest getting a longer screw and see if that will reach the existing bolt. The new screw can't be too long (unless it hits the back of the RV :) ) It will pass through the nut that is lodged in the horizontal tube.
The inner parts (the nut) is available at larger RV supplies or on the internet. Try Walts RV in Rialto CA as a starting point.