Pixelheads dinosaur explorer pack broken

I installed Pixelheads dinosaur explorer pack for my son.

initially it worked fine but after a week the dinosaurs stoped working.

All the dinosaurs are replaced by ordinary animals.  

For example the triceratops shows up as a llama.

I tried removing the pack and redownloading it but the issue persists.

My 6 year old son paid for this pack with money he earned from his allowance so he is really disappointed.