Forgot to look at date when this post was made.   I am having the same
problem with my files and getting the same error.  Files I looked at before
and are already in word 2000 work fine and they open in wordpad.  The "work
around" at the link you give does not work at all for me and i suppose may
not work for others.  It says to save to "rich text format" or "6.0" etc.
This cannot be accomplished because you cannot open the document in the first
place.  You get an error first which blocks you attempts to do this.  I have
searched on this quiet a bit and still have not found a solution to solve the
problem correctly.  

The only solution so far has been just to download another program to view
the files.     I downloaded a program called Jarte here :
http://www.jarte.com/index.html            Click on " give it a try"  It is
free version.

I have no affilliation with this site, but when i did a search, it apparently
gave me an affilliate link.  I think i got the link above without the
affilliate info.

I have tried downloading converters,etc. from works site.  Nothing solved
problem.  This problem just appeared one day.  I don't recall the day etc.
either, so no going back with system settings etc.  I also tried a re-install
of works 2000 from my disc.. Still have the problem.

If anyone has figured this problem out yet, please post again.

Glenn