Video Playback Issues

Hello there,

I'm pretty newbie with C#...

I tried to edit the sample Video playback with my own content ant it works, but when I tried to implement on my own sample app it doesn't ... 

I just want to implement the vuforia videoplayer class on my touch logic (ANdroid)

I have really simple Ui and I don't want to use the setting camera view with all camera options (flash , autofocus, extended tracking ... ) or vuforia Appmanager...

In my project for now the camera detect my video file and get the right path of the video but is look that is not playable ...  but with the original vuforia sample it is playable... 

can anyone suggest the right way to use the vuforia videoplayer class??

thank you

P.S: I develop for Android with Unity extension