The only thing I can recommend is that you try to actually re-create it.
Or ask someone who knows something about resourcepacks to re-create it for you. Afterall there are plenty of really good pictures of the Resourcepack. So if you really dedicate some time to it, you could actually re-create the pack and yeah...

That's all I can recommend :p

Hmm... Maybe it's because Frog2Face is inactive and never bothered to update the download link. Sometimes, people who have been on PMC for many years have retired and went onto their normal everyday lives because they're older and wiser. I wish I had the pack myself so that I could give it to you, but I use a personal pack that I made myself years ago and updated as time flew by. I think the best thing to do for now is to find another cooler Angry Birds pack on the internet or have the determination to make your own. There are plenty of packs out there in this big wide world and there's a possibility that there is another Angry Birds pack floating around. I believe you can do it. Just know that you can follow your texture pack dreams, even if you have to make one yourself. :3