I was able to make my 5th account today using the refer-a-friend key.

I am not sure what solved the problem, so I don't know the exact cause of it for future reference. It might have been the server maintenance reseting all the cache in their servers. It might have been the fact that I waited almost 24 hours before trying it again. It might have been because I did it a friend's house using his email address. It worked and I am pretty excited to finally get started.

Just want to say thanks to all those that replied. Appreciate the quick response.