Okay ladies, thanks for all your help - I did it! Tried the recipe again as written and it worked! This time I paid better attention, as soon as it got to boiling I lowered the heat immediately to simmer. I might have overboiled it a little bit the other day.
I also used a larger and deeper skillet which worked great; when I used the smaller one I think the boiling might have gotten some water into the custard because there wasn't enough room around the custard cups. I have to say, it tastes pretty good! It's not Ben & Jerry's but it's not bad!