I've never seen this problem before so I did a quick search for the error message at http://www.microsoft.com. According to Microsoft, this problem happens when the Autocomplete function tries to look through the list of Web sites that you have visited recently and finds a corrupted folder. Autocomplete is Internet Explorer's capability of filling in a partially typed website name. For example, if you type www.cn and Internet Explorer fills in www.cnn.com, it is Autocomplete that's helping you out.
Microsoft has a procedure for fixing it. I'll just give you the link:
Unfortunately, the method they present is rather brute-force. So, after you're done, Internet Explorer's history will be empty and all your cookies will be gone. Without your cookies, websites that know who you are without prompting for a username and password will forget you.
This was first published in May 2001