Browser cache bug. Empty your cache, try again.
IE's cache is pretty buggy. Actually, the same cache (Temporary Internet Files) is used by any program that uses WinInet.dll for its HTTP and FTP processing, and which chooses to use the cache features. So these bugs affect Internet Explorer, Outlook and Outlook Express (when fetching additional material such as web bugs in HTML email), Windows Media Player, etc.
Other symptoms are missing images, missing stylesheets, failure to View Source, downloading a file and then finding its contents are missing.