App Crushing In Android Version Below 5 (4.2, 4.4)

Hello,
I am using Buildbox 2.2.7 and I used to export app using Android Studio. It seems easy to me. But recently I have found that after adding AdMob ads, my app is crushing (“Unfortunately, <app name> has stopped”) on android 4 (4.2,4.4). It's running nicely on Android 5 & 5+ .
Please Help me to solve the problem.
Here is the log:
-------------------
java.lang.NoClassDefFoundError

in com.google.android.gms.ads.internal.zzs.<init>


java.lang.NoClassDefFoundError: android.support.v4.util.SimpleArrayMap
at com.google.android.gms.ads.internal.zzs.<init>(Unknown Source)
at com.google.android.gms.ads.internal.zzs.<init>(Unknown Source)
at com.google.android.gms.ads.internal.zzb.<init>(Unknown Source)
at com.google.android.gms.ads.internal.zzc.<init>(Unknown Source)
at com.google.android.gms.ads.internal.zzf.<init>(Unknown Source)
at com.google.android.gms.ads.internal.ClientApi.createBannerAdManager(Unknown Source)
at com.google.android.gms.ads.internal.client.zzl.createBannerAdManager(Unknown Source)
at com.google.android.gms.ads.internal.client.zze.zza(Unknown Source)
at com.google.android.gms.ads.internal.client.zzab.zzdh(Unknown Source)
at com.google.android.gms.ads.internal.client.zzab.zzdg(Unknown Source)
at com.google.android.gms.ads.internal.client.zzab.zza(Unknown Source)
at com.google.android.gms.ads.BaseAdView.loadAd(Unknown Source)
at com.google.android.gms.ads.AdView.loadAd(Unknown Source)
at com.secrethq.ads.PTAdAdMobBridge$1.run(PTAdAdMobBridge.java:72)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:829)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:645)
at dalvik.system.NativeStart.main(Native Method)

 

Ok, Thanks !
I was using Android Studio, but now I have tried ADT with API 23 & the app is working on Android 4 now
Buildbox user should only use ADT (Eclipse+SDK), not Android Studio