Issue Resolved
Thanks for the reply, and I am sorry I have not been back to the forum to say thanks until now. As it turned out, I was poking around the forum to see if I could find any other posts that were relevant to this issue, and I found one indicating an issue with the following file:
WA_eCart/PP_ECO_Scripts/PP_ECO_PHP.php
The post provided a link to download an updated/patched version of this file and I figured it could not hurt to try it... so I did. It worked. It corrected the issue.
Thanks again!