sorry for the long wait, unfortunately this has been overlooked for some most of the time.Emails sent to the support address included in the welcome mail you received upon purchase will get answered much faster than forum posts. We try to also keep track of all the form posts, but the channel for priority is email.
Please try to uninstall PDFCreator manually before installing the new version. Do you happen to use Kaspersky Endpoint protection? Another user has reported he needed to turn this off in order to get rid of the error.