There are actually two different players provided to the general public by Macromedia (now Adobe) that handle media:
1. Macromedia Shockwave Player (current version 10.1.11)
2. Macromedia Flash Player (current version 22.214.171.124)
Visit Test Macromedia Shockwave & Flash Players
to find out if you have the updated versions of both players at the same time. Note from the site:If you already have Macromedia Shockwave Player, these movies may trigger an automatic update to your players. Follow the instructions in the dialog boxes that appear to complete the update. Updates can take several minutes with a standard modem connection.
You also should be aware that when you use either of the players, you are downloading information from the site that the media is located. If you have your less privalaged accounts set not to download files from the internet, then this may be your problem.
Hope this helps,