Android Question Newbie - Why the project doesn't run beause Main.bal

#Region  Project Attributes
    #ApplicationLabel: FirstUI
    #VersionCode: 1
    #VersionName:
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: unspecified
    #CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.

End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.

    Private btn_Aenderung As Button
    Private lbl_BezButton As Label
End Sub

Sub Activity_Create(FirstTime As Boolean)
    'Do not forget to load the layout file created with the visual designer. For example:
    Activity.LoadLayout("MAIN")
    'Msgbox("Welcome to B4A!", "")
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub


Sub btn_Aenderung_Click
    
End Sub

Copying updated assets files (1)
** Activity (main) Create, isFirst = true **
Error occurred on line: 31 (Main)
java.io.FileNotFoundException: /data/data/b4a.FirstUI/files/virtual_assets/main.bal: open failed: ENOENT (No such file or directory)
    at libcore.io.IoBridge.open(IoBridge.java:419)
    at java.io.FileInputStream.<init>(FileInputStream.java:78)
    at anywheresoftware.b4a.objects.streams.File.OpenInput(File.java:204)
    at anywheresoftware.b4a.keywords.LayoutBuilder.loadLayout(LayoutBuilder.java:82)
    at anywheresoftware.b4a.objects.ActivityWrapper.LoadLayout(ActivityWrapper.java:209)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
    at b4a.FirstUI.main.afterFirstLayout(main.java:104)
    at b4a.FirstUI.main.access$000(main.java:17)
    at b4a.FirstUI.main$WaitForLayout.run(main.java:82)
    at android.os.Handler.handleCallback(Handler.java:605)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:4441)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
    at libcore.io.Posix.open(Native Method)
    at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
    at libcore.io.IoBridge.open(IoBridge.java:403)
    ... 24 more
** Activity (main) Resume **