the error is occurring on line 4 or 5 of the product detail page:
output started at /home/content/l/i/v/livingtrue/html/Products_Detail.php:5
Look for blank space after a closing PHP tag:
"?> "
or a blank line between a closing php tag and an opening one:
...?>
<?php...
you may also be running into a session problem on the server. Try uploading the attached file and running it.