After you call AddModelError you need to call SetModelValue . That should fix the null reference.
I came across this as I was typing out a nearly identical question/problem. (ie, rendering my view was causing a mysterious NullReferenceException to to be thrown when the user's value failed validation on a particular field.
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.