Errors on uploads

Firstly its WP v2.9.2 (not offered in pulldown) and Gallery v1.5.3

Seems everything is working properly, yet I always get lots of errors when uploading images such as the following below.
Seems the gallery works fine, and the theme… Any idea what the errors are and how to fix? The progress bar still works as the errors are being displayed…
(Just a partial list of errors below – links modified with generic text for this forum post):

ERROR: PICT0139 (2).JPG :
Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, ‘gde_conflict_check’ was given in /home/content/websitelink/html/wp-includes/plugin.php on line 339

Warning: session_start() [function.session-start]: Cannot send session cookie – headers already sent by (output started at /home/content/websitelink/html/wp-includes/plugin.php:339) in /home/content/websitelink/html/wp-content/themes/shopperpress/functions.php on line 21

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at /home/content/websitelink/html/wp-includes/plugin.php:339) in /home/content/websitelink/html/wp-content/themes/shopperpress/functions.php on line 21

Warning: Cannot modify header information – headers already sent by (output started at /home/content/websitelink/html/wp-includes/plugin.php:339) in /home/content/websitelink/html/wp-content/plugins/nextgen-gallery/admin/upload.php on line 31
0
ERROR: PICT0129 (2).JPG :
Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, ‘gde_conflict_check’ was given in /home/content/websitelink/html/wp-includes/plugin.php on line 339

Warning: session_start() [function.session-start]: Cannot send session cookie – headers already sent by (output started at /home/content/websitelink/html/wp-includes/plugin.php:339) in /home/content/websitelink/html/wp-content/themes/shopperpress/functions.php on line 21