Android Question Mike Penz MaterialDrawer library

[PABLO2013]

I have the following error I want some help thanks

** Activity (main) Create, isFirst = true **
java.lang.NoClassDefFoundError: Failed resolution of: Lcom/mikepenz/fastadapter/adapters/ItemAdapter;
    at de.donmanfred.DrawerBuilderWrapper.Initialize(DrawerBuilderWrapper.java:74)
    at de.donmanfred.MaterialDrawer.main._activity_create(main.java:547)
    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:351)
    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 de.donmanfred.MaterialDrawer.main.afterFirstLayout(main.java:105)
    at de.donmanfred.MaterialDrawer.main.access$000(main.java:17)
    at de.donmanfred.MaterialDrawer.main$WaitForLayout.run(main.java:83)
    at android.os.Handler.handleCallback(Handler.java:883)
    at android.os.Handler.dispatchMessage(Handler.java:100)
    at android.os.Looper.loop(Looper.java:224)
    at android.app.ActivityThread.main(ActivityThread.java:7561)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:995)
Caused by: java.lang.ClassNotFoundException: com.mikepenz.fastadapter.adapters.ItemAdapter
    ... 18 more
** Activity (main) Resume **