Patrick,
oh dear, i hope i am wrong but it looks like there is a piece missing from your chassis?
Take a look at this dutch guys website in his section called Building Part 2.in a section titled "Next Milestone"
http://www.marlinsportster.nl/
In his words.............
The chassis missed the brackets to put the door pins on. Somehow forgotten? Don't know, but after some emails, I got a nice pair of brackets from Mark to bolt on. Perfekt Job from him.
I hope I am wrong?
Peter