Android native extension packaging error

Hi,

I have been working on a native extension. It packages and runs fine on ios, but when I try to launch my app on an android device I get the following error,

!MESSAGE Error occurred while packaging the application:

null

!STACK 0

java.lang.NullPointerException

          at java.util.zip.ZipFile.getInputStream(ZipFile.java:194)

          at com.adobe.air.apk.APKPackager.processExtensions(APKPackager.java:228)

          at com.adobe.air.ApplicationPackager.createPackage(ApplicationPackager.java:65)

          at com.adobe.flexbuilder.multisdk.apollo.export.AIRAPKPackager.createUsingPackager(AIRAPKPackager.java:245)

          at com.adobe.flexbuilder.multisdk.apollo.export.AIRAPKPackager.create(AIRAPKPackager.java:575)

          at com.adobe.flexbuilder.multisdk.apollo.export.AIRAPKPackager.create(AIRAPKPackager.java:138)

          at com.adobe.flexide.multiplatform.android.launching.ADBLaunchHandler.doPackage(ADBLaunchHandler.java:423)

          at com.adobe.flexide.multiplatform.android.launching.ADBLaunchHandler.launch(ADBLaunchHandler.java:350)

          at com.adobe.flexide.launching.multiplatform.MultiPlatformLaunchDelegate.launch(MultiPlatformLaunchDelegate.java:184)

          at com.adobe.flexide.launching.AbstractFlexLaunchDelegate.launch(AbstractFlexLaunchDelegate.java:244)

          at com.adobe.flexide.launching.AbstractFlexLaunchDelegate.launch(AbstractFlexLaunchDelegate.java:134)

          at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:854)

          at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:703)

          at org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:928)

          at org.eclipse.debug.internal.ui.DebugUIPlugin$8.run(DebugUIPlugin.java:1132)

          at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)

I am using Flash Builder 4.7, latest android SDK and Flex 4.12 with air 13 beta.

Any ideas?