Commented Unassigned: Item has already been added. Key in dictionary: 'A' Key being added : 'a' [36]

Hello
This is a .net 4.0 windows form project.
When i press login button , i get an exception:
The type initializer for "Tacirler_Earsiv.Genel" threw an exception

In the inner exception says:
Item has already been added. Key in dictionary: 'A' Key being added : 'a'

"Genel" class is very simple and short. It has a few static properties. I just assign userName and userId info to its properties.

Do you have any idea?
I have attach mapping.txt, obfuscar.xml and Genel.cs.

Comments: I have sent you an email. It contains my sample project. Thank you.