Thank you Michael.
I'm a Windows 98 user, trying both IE5 and Netscape 4.something (oddly, the problem occurs in both). I tend to clear my local cache using (i) the 'delete files' and 'clear history' options in the Settings > Internet Options panel, or (ii) just diving into the directories and clearing out the files in the Cookies and Temporary Internet Files directories.
At least the time delay stops me wasting quite so much time at work...
[This message has been edited by Lux (edited 08-09-2001).]