I assume that what you are showing above is your metarig and in that case I’m not surprised.
The thing to understand about rigify is that you have to follow the recipe. adding an extra set of arms is ok, but adding additional joints to limbs is going to confuse the algorithm that expects the two boned arm.
I just tried to see if deleting both the chest and pelvis bones would result in your error and No. it appears you dont need those bones to generate a rig.
The major problem you added to or subdivided the superlimbs which would scare the compiler, I mean the human form does not have three elbows. If you want bendy arms just change the type to tentacle in pose mode . Or youknow just use the normal arms and abuse the hell out to the tweak bones to get the rubberhose arm effect.
