Problem with the 21/9 bigbox theme

[tartinons]

Hello, I am a new bigbox user. and i have problems with theme.

I wanted to install the theme 21/9 but I encounter bugs. this one :  

 

I do not have the selection arrow that appears as on the video, and on the game pages I have a black background, the image seems to be on the right side of the theme rather than left.

Do I miss something for the theme function?

 

Some screenshot of my bigbox :

 

No arrow :

 

Black background on left, and the game picture is on right part of the screen behind the wheel (not like the video ? )

 

Do you know what I miss? Thanks ?