Help with GUI attempt #3 :P

Question

Vulpes, I am not sure if you read my last post in the old GUI thread, but I said I spent around 7 minutes to find that Form Designer lol...
Anyways I have done what you told me to do in last thread.
I found few more bugs, could you help me fix it ?
Like it will crash when I click previous and next button for like 3 or 4 times then they get disabled. My skip to first or skip to last works fine.
I also added option that date of birth calendar is not enabled in the view mode but only in edit mode, same with age box. Cause its the part of the requirements. But the age wont calculate automatically, logically when you select new age in the calendar it should update age box automatically right.
Its something about array, when my teacher crashed it he was saying something about how array is bad you should use some <List> property that I have no idea about.