Qdig-WP plugin – thumbs not showing

I asked this on the plugin author’s forum, but, due to life happening, he may or may not see it there. ( https://forums.randomfrequency.net/viewtopic.php?t=32 )

I’m using the Qdig-WP Plugin on several sites now, and for some reason, I can not get thumbnails to appear on any of the sites.

The latest site that I have added with this same result is https://beachracing33x.com/photos/

I enabled the diagnostic message and received this:

Diagnostic Messages:
Qdig version is 1.2.9, PHP Version is 4.3.11 on Linux
Server Software is Apache/1.3.33 (Unix) mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 PHP/4.3.11 mod_ssl/2.8.22 OpenSSL/0.9.7a FrontPage/5.0.2.2635
$qdig_url is ./
$php_self is /index.php
$script_name is /index.php
Query string is pagename=photos&page=
$pwd is ./2005, $chroot_dir is (empty)
$is_included is TRUE, $header[‘force_ena’]/[‘force_disa’] are FALSE/FALSE
$fs_base_path is /home/beachrac/public_html/pix/
$base_dir is /home/beachrac/public_html/pix
$url_base_path is /pix/
$qdig_files is qdig-files (exists, with 775 perms), $cnvrtd_dir is (empty)
$cnvrtd_files_root is ./qdig-files/converted-images/ (exists, with 777 perms)
$captions_root is ./qdig-files/captions/ (exists, with 775 perms)
$convert_magick is FALSE, $convert_cmd is /usr/bin/convert (exists, with 755 perms)
$convert_GD is FALSE, GD version 2 detected, phpinfo() function is enabled
$convert_writable is FALSE, $convert_readable is TRUE, $reqd_view is thumbs
$thmbs_ena is TRUE, $namelinks_ena is FALSE, $check_security is TRUE
$is_readable_disa is FALSE, $file_exists_disa is FALSE, $compat_quote is TRUE
Execution time is 77 milliseconds, max_execution_time is 30 seconds

In firefox, if I right-click one of the links that is supposed to be a thumbnail, I get this message:

Warning: Cannot modify header information – headers already sent by (output started at /home/beachrac/public_html/wp-content/themes/GreenTrack/index.php:9) in /home/beachrac/public_html/wp-content/plugins/qdig/index.php on line 665

Warning: Cannot modify header information – headers already sent by (output started at /home/beachrac/public_html/wp-content/themes/GreenTrack/index.php:9) in /home/beachrac/public_html/wp-content/plugins/qdig/index.php on line 666

If anyone could suggest something I can do to fix this, I’ll certainly be most grateful.