I don't know what's different, but now it works...
Have you guaranteed that in the Sections dictionary of the first item in the ItemList there is actually an entry for "Personality". If there is no entry then the error you are seeing is what you would get. The Line Series uses the values of the first item in the item source to determine appropriate axes to use.
If the value is null it will fail with an exception similar to the one you describe (the one in your question is the exact phrasing for the error?).
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.