I get this in email a fair bit.
There are 3 reasons why this can happen
[li]Your Browser is not accepting the cookies from allakhazam.com. ensure they're tunred on, in IE 6, you may need to force enable cookies from allakhazam.com. (under privacy)
[li]Your system clock on your computer is not set properly. This means the system expires the cookies as soon as it gets them.
[li]Your Broswers cache is caching things which it should not. People on Prodigy seem to have this problem a fair bit - I think Prodigy does very agressive caching. You may need to hold down the shift key and reload the page.
Hope that helps