I just noticed this here, so I don't know if this information will be relevant or not, (not sure if the problem is solved or not...). In IE 6 and maybe 5.5 there is a setting under Tools --> Internet Options - and on the first tab Temporary Internet Files ---> Settings. In this window there is a setting for when to check for newer pages, this may be set to something other than AUTOMATICALLY, if it is change it. This will tell IE to check for a new page every time you visit that site. This is important for sites that use cookies to identify you. Because the cookie remembers the first instance it was created, not subsequent visits. Or, if this fails, per Magister Ventrue's suggestion, reset the cookies or delete them so a new one can be created.
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"When the long winter nights come on and the wolves follow their meat into the lower valleys, he may be seen running at the head of the pack through the pale moonlight or glimmering borealis, leaping gigantic above his fellows, his great throat a-bellow as he sings a song of the younger world, which is the song of the pack. "Old longings nomadic leap, Chafing at custom's chain: Again from its brumal sleep Wakens the ferine strain."" -Jack London, The Call of the Wild