Your problem is here
HTML Code:
<a href='index.php?showimage=<IMAGE_ID>' onclick="window.open('index.php?popup=comment&showimage=<IMAGE_ID>','Comments','width=480,height=540,scrollbars=yes,resizable=yes');">Comments (0)</a>
Fix.
HTML Code:
<a href='<SITE_URL>p/<IMAGE_ID>' onclick="window.open('<SITE_URL>comment/<IMAGE_ID>','Comments','width=480,height=540,scrollbars=yes,resizable=yes');">Comments (0)</a>
You need to do similar adjustment in the popup comment template
HTML Code:
<form action="...">...</form>
I updated the htaccess rules on
Pixelpost Template Page of The World In 35mm to include a comment/submit rule.
If you are going to use mod_rewrite URLs for pixelpost links, don't mix, some mod_rewrite URLs and some standard PP URLs. It just causes problems. And prefix all URLs with <SITE_URL>, since mod_rewrite URLs make using relative HTML links difficult.