Android Question Card flip (flip between 2 images)

I try example from @cimperia and get error:

** Activity (main) Resume **
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
Error occurred on line: 47 (B4XDeck)
java.lang.ArrayIndexOutOfBoundsException: length=54; index=54
at com.simplysoftware.flipcards.b4xdeck._initialize(b4xdeck.java:121)
at com.simplysoftware.flipcards.main._activity_create(main.java:409)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:348)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at com.simplysoftware.flipcards.main.afterFirstLayout(main.java:107)
at com.simplysoftware.flipcards.main.access$000(main.java:19)
at com.simplysoftware.flipcards.main$WaitForLayout.run(main.java:85)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6518)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
** Activity (main) Resume **

I can't find a solution. Does anyone know?