In some circumstances, attempting to package an AIR application for Apple iOS platform using ipa-ad-hoc and ipa-app-store targets can result in a NullPointerException. A workaround for this problem may be to use a debug version of your SWF in the package.
When using the Project->Export Release Build… menu item to create a package, click Next on the first screen. You will notice that it will build the release SWF as it switches from this screen to the Package Settings screen.
Before you click Finish on the Package Settings screen of the Export Release Build dialog, go to your project within Finder (or File Explorer on Windows). With the Export Release Build dialog open you will not be able to do the next step within Flash Builder and you will have to do it within Finder. Copy the ePresenter.swf file found in the bin-debug directory and replace the same file in the bin-release-temp directory with the one from the bin-debug.
Once you copied the debug version into the bin-release-temp folder, you can click Finish. When I tested this, it was able to create the IPA.