AppEntry not found boot crash in android

Hi

I have an app in play store which is crashing on boot to some users.

The error posted is:

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{air.appname/air.appname.AppEntry}: java.lang.ClassNotFoundException: Didn't find class "air.appname.AppEntry" on path: DexPathList[[zip file "/mnt/asec/air.appname-1/pkg.apk"],nativeLibraryDirectories=[/mnt/asec/air.appname-1/lib, /vendor/lib, /system/lib]]

at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2232)

at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2358)

at android.app.ActivityThread.access$600(ActivityThread.java:156)

at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1340)

at android.os.Handler.dispatchMessage(Handler.java:99)

at android.os.Looper.loop(Looper.java:153)

at android.app.ActivityThread.main(ActivityThread.java:5299)

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:833)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)

at dalvik.system.NativeStart.main(Native Method)

Caused by: java.lang.ClassNotFoundException: Didn't find class "air.appname.AppEntry" on path: DexPathList[[zip file "/mnt/asec/air.appname-1/pkg.apk"],nativeLibraryDirectories=[/mnt/asec/air.appname-1/lib, /vendor/lib, /system/lib]]

at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:53)

at java.lang.ClassLoader.loadClass(ClassLoader.java:501)

at java.lang.ClassLoader.loadClass(ClassLoader.java:461)

at android.app.Instrumentation.newActivity(Instrumentation.java:1054)

at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2223)

... 11 more

I have looked arround but coudln't find information of a similar issue. Anyone knows what may cause this?

Thankyou