Thank you for getting back. I had the same idea and put the redirect at the end of the php section. But that didn't work. I also tried deleting lines 115-302, as well as the store cart summary behavior and the store cart details behavior from the confirm page. My idea was, that those values would already have been provided by confirm2.php, but I still had the same result.
I tried to attached both pages, but I have problems uploading the pages. For both pages I get the message "Upload errors: ... invalid file".