Can't switch to another scene

Hello every one , i had one issue here. I’m building an vehicle showcasing App with the ability to switch between 3D and augmented reality.
The AR part i’m using the ARToolKit plugin from Unreal4AR , which worked out great the first time when i packaged out it for my Android device.
But now it don’t work anymore , usually i load the 3D/AR scene by clicking on a button in my menu page , but now it just gets me a brief black screen and go back to my menu page.
I’m trying to find the errors , here’s sometime i could find in the log

“LogStats:Warning: MetaData mismatch. Did you assign a stat to two groups? New //STATGROUP_Threads//FLauncherTask///Thread_312c_0///####STATCAT_Advanced#### old //STATGROUP_Threads//FLauncherTask///Thread_2244_0///####STATCAT_Advanced####”.

Could any one help , please ?