When you use Event 2.0 part and you use Confirm Email, if both of the emails don't match and you untick 'Use this as my billing information' and try and submit the transaction, you get the error: Confirm Email: Addresses do not match Since the option is unticked, you cannot edit the email that is in the confirm email box.
Download and install the latest Service Pack which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.
Steps to Duplicate
Create an Event Registration Form Part, enabling the Confirm Email
Go to the Event Registration form page
Enter 1 ticket and click next
On the page where you enter the registrant information, enter details but make sure the Email & Confirm Email don't match, and untick 'Use this as my billing information'