No idea, but it looks like you aren't the first; http://forums.adobe.com/message/4729459
Though I also found this http://johnlindquist.blogspot.ie/2011/03/top-10-air-26-for-ios-questions_21.html (yes, I know it's AIR 2.6, but the principal is the same) - check your app descriptor file is ok. Check the bin-release directory is a) writable and b) there. Perhaps do a couple of "Project Clean" and maybe even delete the bin-release to get it to regenerate... You know, kick it and hope.
Indeed I am not, but the explained issue in that thread is exactly what I'm facing, the release swf isn't build.
The "help" Adobe is offering in that thread (sending in the project) isn't much more than a bad joke. Sure I violate my corporate guidelines and send in all of our code. Yeah right.
Anyway, thanks for your help! Will definitely go through the options described at stackoverflow.
If that doesn't help, I might just set up a new project, import all class manually (which are a lot!) and see if that solves the problem.
4.7 really has been a huge disappointment till now. It it wasn't for the iOS simulator support, I'd be back to 4.6 this instant. It really is just wrestling with a vastly flawed IDE at this point and I hope Adobe is adressing the issues quickly.
So, even after setting up a new project, the problem didn't go away. Seems as if the problem sits within the libraries I'm using, though none of them do show any errors or problems.
I was wrong accusing Flash Builder on this one! I've had two asset source paths that overlapped and apparently, Flash Builder can't handle that when you try to make a release build. Again, debugging always worked fine. I didn't get any warnings either, so it took me quite some time to even think that that might be an issue.
Still, the pletheora of Flash Builder bugs remains!
Found a new one with is also rather annoying recently;
Open the local history of a file and try to copy some text from that file, you'll instantly get a java nullpointer, resulting in the fact that the text isn't copied to the clipboard.
That last edit was actually based on a premature thought of success. Unfortunately, the project still doesn't compile. There are no errors or problems whatsoever in neither of the library projects or the main project.
Edit3: - Finally solved it!
After re-installing FB4.7, thus overwriting the old installation with all it's SDKs, I figured that the merged SDKs might have been causing this issue.
I've merged SDKs several times before using FB4.7 and it worked fine all the time, the absolutely ridiculous way Adobe forces us to update the AIR SDK with 4.7 is so prone to error, that I might have made a mistake this time though.
So for everyone who struggles with this issue as well, make sure your SDKs are in order! Also check the version numbers in air-sdk-description.xml which is located in the AIRSDK folder.