SP1 --> Internet Explorer 6 Service Pack 1, which is the current version. You can tell which version you're running by going into IE, selecting 'Help > About Internet Explorer', then looking under the 'Update Versions' section. If it says SP1, then you're running the most current version. If not, you need to go to Windows Update and get it.
http://www.windowsupdate.microsoft.com SP1 will be under 'Critical Updates' if it's determined that you need it.
If you're already running SP1, then you might want to run the Repair routine for IE.
Go into Add/Remove Programs in Control Panel, and you should see an item for "Microsoft Internet Explorer 6 Service Pack 1 and Internet Tools", or something similar. Select it, then click on the Add/Remove button. Then at the next dialog box, select the radio button for 'Repair Internet Explorer', and click OK. This will repair IE, restore missing files/settings/etc. It'll most likely call for a reboot of your computer when finished.
After doing that, you can check and see if you can view Flash animations. If not, you might need to go to the Macromedia site again, and see if the Flash player needs updating again -- performing a Repair on IE can necessitate reinstalling a few components in some cases.