This problem was marked as "SOLVED" by the Incomedia staff, however, it's certainly not solved for me.

Please compare these two web pages:

https://www.paramountequestriancentre.com/shows.php

and

https://www.paramountequestriancentre.com/camps.php

The "shows" page is fine. However, you can see a thin white line on the left and right sides on the "camps" page (as well as other pages on this site). Those spurious white lines should not be there. I haven't figured out how to make them disappear. Ko Asim's suggestion to the previous post on this matter does not work for me.