Thanks for your assistance Issach! The error message is on the web page itself when using Safari. I filled in the four windows with the correct information: SocialFans Counter (the app), "counting my followers, and then my web site address in the last two windows. Then I click the “Yes, I agree” box and then the “Create your Twitter app” button. That is when I get the error message in a red-shade box at the top of the web page.
When I try to create my Twitter app on Chrome and Firefox, I get this error message:
Error Validation failed: SocialFans Counter is already taken for Name