I had the same issue with the Sat afternoon session, so I decided to just buy Fri night tickets. The good news is I could buy 4 tickets instead of just 2, so my wife and I can bring some friends.
I wouldn't blame these issues on AHA, but on Ticketmaster. Selling tickets online is supposed to be their area of expertise, but it seems like there are lots of little problems with their system. First, the system tells me my member number is wrong when it clearly was not. Then, when I decided to try for a Fri ticket instead, it accepted my member number and told me I was approved for the Fri might tickets with the farm to table option, which I had not selected. Fortunately when I got to the payment page, farm to table wasn't on my bill. Also, why is ticketmaster the only site that I visit that has that extra credit card verification password? I use Ticketmaster once every couple of years and can never remember it.