When running the html-wrapper ANT task with no specific arguments, the task writes the following output:
[ant:html-wrapper] Error outputting resource: playerProductInstall.swf
[ant:html-wrapper] java.io.IOException: Stream closed
The result of the task is that all files have correctly been generated except for 'playerProductInstall.swf', which is there, but has no content (0 Kb).
This seems to be a regression bug. I have run the same task on the same project against Adobe Flex 4.6, which works as expected.