After our organization updated to the latest version of CiviCRM, our users started receiving the following error after registering for events on our website:

*Sorry but we are not able to provide this at the moment.
Could not find valid value for id
Return to home page.*

The user is properly registered on our system and receives a confirmation email.  It seems to be a problem with the thank you screen.  The configuration of the thank you screen is the same as before.

Ideas?