I run into the same problem while working on some sort of file synching task.
Trying to read the file.modificationDate or creationDate results in an error: "Error #3003: File or directory does not exist."
I have obeserved that this only happens for files that were packaged with the app (and placed in the File.applicationDirectory).
Files that my app has downloaded and saved to the device (File.applicationStorageDirectory) do have a valid creation date and modification date.
Maybe the File.applicationDirectory has different rights?
Does anybody have a solution or workaround for this?
maybe it is the authority setting on Andriod due to secrity issue?
I just ran into this too. It's still happenning on Adobe Air SDK 3.7. Perhaps this is the wrong forum for this question.