The bug appears to be security-related. I haven't investigated it enough to see if it's a genuine bug in FP10 or if it's just a side-effect of tightened security. I tend to think the latter, but the upshot is that FP10 is now in release-candidate stage and it's not known if this problem will propagate to the actual release. And since new Flash releases get download numbers that kick sand in the face of that "world record download" that FF3 boasts, it's best to err on the side of caution and fix the bug soon.
That's the bad news. The good news is that fixing the bug server-side is trivial and involves commenting out one line of PHP on your server code. Here's a blog-post with the fix.
http://www.swapdepths.nl/2008/09/04/swx-and-fp10/
I just tried this on thecodezone.com, and it works just fine. Again, I'm not sure what that line actually did, but removing it fixes FP10 and appears not to break earlier players, so it's a good fix.
And I guess apologies in advance if you're an early-adopter of Flash players and you found my daily puzzles broken. Thankfully the bug only happened with my low-bandwidth (in relative terms) daily puzzles and not in the "play n share" versions that are now filling up every cheapo Flash game portal on the intertubes.
