Even using B4A v6, I was getting the error:
java.lang.NoClassDefFoundError: com.google.android.gms.analytics.GoogleAnalytics
Apparently the latest play services download does NOT include a file called "google-play-services.jar" anywhere.
So I spent a bunch of time and found that I needed to add this line in my main activity to fix this issue:
#AdditionalJar: com.google.android.gms:play-services-analytics