404 Error in IE6 but not Firefox???

I am getting errors in IE6 but not Firefox.

To reproduce, here is the page:

http://erwisdom.com/brooks-top-rv-and-investing-lists/

Click on the first hypertext:

Top Books on Fulltiming in an RV

It causes an Error 404 in IE 6.0.

I did try updating my Permalinks and it didn’t help.

Any help would be appreciated.

Thanks,

Brooks