UPDATE:
I think these DFC linkage rods are defective. I tried screwing one of my older Align linkage rods into the DFC ball links and they screwed in just fine.
I emailed A Main Hobbies, the greatest online hobby store in the world, and they ONCE AGAIN came through for me. They sent out a replacement pack (qty 4 rods/ball links) for free, no questions asked!! Seriously, I haven't had a bad experience with these guys. Awesome customer service, good prices, rewards points, and free shipping on qualified orders!!
Anyway, thanks for the suggestions!
Have a great weekend !
Ernie