Some flash files don't appear on macintosh

I've installed the latest flash player on a macintosh 10.4.11. But I've noticed that a few flash sites don't appear. Among them the flash player page itself:
As you can see, where the flash movie should play there's just white space. Both on Safari and Firefox for Mac.

I've also tried in on another mac so it's not just my computer.
I've checked the version on: and that flash movie runs fine. It also says: 'You have version 10,0,32,18 installed'
At home on a pc these pages (like work fine. What kind of thing could make the swf disappear on a mac?