Ok, this is likely the cause of these problems. You should update to the latest release of eCart. At the time of this posting the latest release is 4.5.2. After you update to this version you should make a backup of your current files, then try to update the local checkout that is applied to your confirm page. If this does not yield the correct result then you may need to recreate the checkout pages with the new eCart using the checkout wizard.
Make sure you take a look at the documents found here:
In the right side of the page under the heading 'Additional Help' are some documents about downloading and installing the extensions.