Re: .and now my rear rim is screwed up....halp
I have built eight bikes, some with older (60's and 70's) rims, some were new bikes. All had the stock rag joint sprocket mount and I have not had any problems with any of them.
I'll bet your wheel didn't have the spokes tightened correctly, or maybe not at all as most wheels are "machine built" and about every third spoke is actually tensioned right.
Bummer to pay extra for a wheel that didn't hold up.