(First check that you have checked the box Enable Plug-ins in Safari Preferences/Security! )
Update 10.6.4 included an out-of-date version of FlashPlayer*. Try deleting it and installing the latest one from Adobe
even if it has the same version number as the one you have:
The latest version of Adobe FlashPlayer can be obtained from here:
http://www.adobe.com/shockwave/download/download.cgi?P1ProdVersion=ShockwaveFlash
(You can check here:
http://www.adobe.com/products/flash/about/ to see which version you should install for your Mac and OS.
You should first uninstall any previous version of Flash Player, using the uninstaller from here (make sure you use the correct one!):
http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_14157
and also that you follow the instructions closely, such as closing ALL applications first before installing. You must also carry out a permission repair after installing anything from Adobe.
* To avoid this situation in the future, Apple recently announced that Macs would in future not have Flash Player pre-installed, precisely to avoid this situation, saying:
We're happy to continue to support Flash on the Mac, and the best way for users to always have the most up to date and secure version is to download it directly from Adobe.
They also noted that this will be happening across all Macs in the future, though there may be some models still in the channel with Flash pre-installed.
(Source:
http://www.engadget.com/2010/10/22/apple-responds-on-missing-flash-in-new-macboo k-airs-says-get-us/ )
It is also interesting to note that
more than half of the security issues addressed by the recent security update 2010-007 (for Leopard and Snow Leopard) were Flash related:
http://photos.appleinsider.com/cve.001.jpg
"the most security vulnerabilities by far are associated with the Adobe Flash plugin, with a whopping 55 issues listed, the "most serious of which may lead to arbitrary code execution," Apple reports in its Apple Product Security update.
The security issues related to Flash are in fact the stated reason why Apple is backing away from bundling the plugin with its new computers. Apple began shipping the MacBook Air without Flash installed, noting that customers could install the plugin on their own to ensure they had the latest, most secure version.
However, testing indicates that in normal operation, Flash can also consume dramatic amounts of battery life just to animate web ads in the background, resulting in as much as two hours of lost productivity on a single charge."
source:
http://www.appleinsider.com/articles/10/11/10/adobeflash_contributes_largest_number_of_security_patches_in_apples_mac_os_x_10_56.html