We have not experienced the issue until today, so I suspect something has changed on the website to cause it. Moreover, it appears to be affecting older Internet Explorer versions only (IE8 and 9). Too bad those of us with older operating systems can't upgrade to IE10 (need Windows 7 or 8)! Hopefully it is fixed soon!
Edit: The 'officially supported' browsers for Geocaching.com according to the support doc are
•Microsoft Internet Explorer 8.0+
•Mozilla Firefox 4.0+
•Google Chrome
•Opera 11.5+
•Safari 3.0+