Good night

I have a problem with Kde Neon, I want to participate in the development of Plasma Mobile, and followed the tutorials and everything but gave me error, but when you install the components of Kde Neon I began to work until you restart the pc and when I went to login to log in would not let me enter and I got the following.

http://postimg.org/image/xucx71btz/

Then you uninstall Kde Neon delete all the previous system and follow the instructions found on the official site of Kde Neon and still giving me problems,

I need help I am motivated to help.