In case anyone else has this problem. I had to clear my dotnetnuke.com cookies to log into DotNetNuke.com
1. On my Windows XP machine I went to:
C:\Documents and Settings\(my user name)\Cookies
(replace "(my user name)" with the username of the user you are logged into your machine as)
2. Found the one or two cookies with "dotnetnuke" in their names and deleted them:
(my user name)@www.dotnetnuke[-].txt
(one of the possible ones has "www" the other doesn't. They also will have a number between the "[]" brackets)