Oh heavens, this post is still going! And I've only just noticed 4 years later!
I never thanked Swansonville for a very clear answer. I did follow your advice and found it easy to work around. It just took off after that. Since 2007 to date I have added several hundered to my tree. So far the Ahnentafel has managed to accomodate most of my relatives - and it really is very, very useful once you get past the hundred mark.
Thanks so much again Swansonville - 4 years late but better than never. :)