Error Opening html40.pdf.gz

I am using WinZip 9.0 SR-1 (6224) to open html40.pdf.gz from http://www.w3.org/TR/html4/.  Unfortunately, I receive the following error when trying to decompress the file:  Invalid Archive Directory.  (I also receive this error when I try to open html40.ps.gz.)
 
I have read the GZIP code is incorporated into WinZip, so there should be no problem using WinZip to open this file.  Am I doing something wrong?  Do you have another compressed version of html40.pdf that I can download or receive?
 
Thanks!
Matt Buie
Little Rock, AR
******************************************************************************************
The information contained in this message, including attachments, may contain 
privileged or confidential information that is intended to be delivered only to the 
person identified above. If you are not the intended recipient, or the person 
responsible for delivering this message to the intended recipient, ALLTEL requests 
that you immediately notify the sender and asks that you do not read the message or its 
attachments, and that you delete them without copying or sending them to anyone else.