Crashlytics NoClassDefFoundError: com.crashlytics.android.answers.Answers

I am getting a project from another developer to fix minor application issues when I run my application on a device. I am getting the error:

15142-15142/com.etripconcept E/AndroidRuntime﹕ FATAL EXCEPTION: main java.lang.NoClassDefFoundError: com.crashlytics.android.answers.Answers at com.crashlytics.android.Crashlytics.<init>(Crashlytics.java:224) at com.crashlytics.android.Crashlytics.<init>(Crashlytics.java:207) at com.crashlytics.android.Crashlytics.<init>(Crashlytics.java:202) at com.etripconcept.SplashScreenActivity.onCreate(SplashScreenActivity.java:16) at android.app.Activity.performCreate(Activity.java:5163) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2061) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2122) at android.app.ActivityThread.access$600(ActivityThread.java:140) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1228) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4895) 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:994) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761) at dalvik.system.NativeStart.main(Native Method)

I'm new to Android development, so this might be a stupid question, but Google doesn't say anything about it. I am using Android Studio 1.2.2 on Win 8.1