Cache:
First try clearing the browser cache for the version you're using: 
  • Safari 3.x for Mac OS X

    • Click the Safari menu. 
    • Select Empty Cache. 
    • Click Empty. 
    • Safari 3.x for Windows 
    • Click the Edit menu. 
    • Select Empty Cache. 
    • Click Empty. 
Cookies:
If clearing the cache doesn't fix the problem, next you may want to try clearing the browser cookies. Important! While deleting the browser cookies may fix the problem, it also removes your saved settings for sites you've previously visited. 
  • Safari 3.x for Mac OS X

    • Click the Edit menu
    • Click Preferences
    • Click Security
    • Click Show Cookies
    • Click Remove All
    • Click Done
    • Close the Preferences dialog box
  • Safari 3.x for Windows

    • Click the Safari menu
    • Select Preferences
    • Click Security
    • Click Show Cookies
    • Click Remove All
    • Click Done to close the cookies list
    • Close the Preferences dialog box
Note:
To find the version, in Safari: On Mac OS X, click Safari, and then click About Safari. On Windows, click Help, and then click About Safari.