Know f-all about the mac but have you just installed it, the plug in I mean?
edit: try this (older versions)
<a class="postlink" href="http://mac.oldapps.com/flash_player.php?system=mac_os_x_10.6_snow_leopard_intel" onclick="window.open(this.href);return false;">http://mac.oldapps.com/flash_player.php ... pard_intel</a>
Use this to un-install your old flash first (it's free)
<a class="postlink" href="http://www.macupdate.com/app/mac/25276/appcleaner" onclick="window.open(this.href);return false;">http://www.macupdate.com/app/mac/25276/appcleaner</a>