Please use your browser's "Back" button and try again.
The one reason I have found that this error message you received happens is that you may have bookmarked this "email" page form at one time and by using the bookmark to return to it you will get this error.
You need to actually go to the page containing the email link and click it on that page. This is the only way to avoid the error.
If this does not help please email me at firstname.lastname@example.org