If you have been using the FP 10 RC and came across a site or widget using SWX, you undoubtedly noticed that it wasn't working. After a couple of days of back-and-forth on the SWX mailing list, the issue has been found and a solution posted.
[Update September 5, 2008 - a different fix was suggested in an attempt to allow SWX to continue to be used by hitting the gateway directly, allowing for easier debugging. Code below reflects this update.]
The problem is that FP 10 does not like one of the headers returned from SWX. To fix the issue, open SwxAssembler.php and change line 538 from:
header('Content-Disposition: attachment; filename="data.swf"');
header('Content-Disposition: inline; filename="data.swf"');
This seems to fix the issue, as all SWX sites this has been tested on now work in FP 10.