HTTP-fout 500 (Internal Server Error)

We are experiencing a lot of 500 Internal Server Error since we’ve installed your NextGen plugin.

these are the last 6 server errors:
[Tue Mar 26 14:12:19 2013] [warn] [client 78.22.89.200] mod_fcgid: stderr: PHP Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 491520 bytes) in /var/www/dedigitaleboekentas.be/dedigitaleboekentas.be/wwwroot/wp-content/plugins/nextgen-gallery/admin/manage-images.php on line 451, referer: http://dedigitaleboekentas.be.apache08.hostbasket.com/wp-admin/post.php?post=384&action=edit&message=6
[Tue Mar 26 15:11:00 2013] [warn] [client 78.22.89.200] mod_fcgid: stderr: PHP Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 491520 bytes) in /var/www/dedigitaleboekentas.be/dedigitaleboekentas.be/wwwroot/wp-content/plugins/nextgen-gallery/admin/manage-images.php on line 451, referer: http://dedigitaleboekentas.be.apache08.hostbasket.com/wp-admin/post.php?post=400&action=edit&message=6
[Tue Mar 26 15:17:18 2013] [warn] [client 78.22.89.200] mod_fcgid: stderr: PHP Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 491520 bytes) in /var/www/dedigitaleboekentas.be/dedigitaleboekentas.be/wwwroot/wp-content/plugins/nextgen-gallery/admin/manage-images.php on line 451, referer: http://dedigitaleboekentas.be.apache08.hostbasket.com/wp-admin/post.php?post=367&action=edit
[Tue Mar 26 15:52:08 2013] [warn] [client 78.22.89.200] mod_fcgid: stderr: PHP Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 491520 bytes) in /var/www/dedigitaleboekentas.be/dedigitaleboekentas.be/wwwroot/wp-content/plugins/nextgen-gallery/admin/manage-images.php on line 451, referer: http://dedigitaleboekentas.be.apache08.hostbasket.com/wp-admin/nav-menus.php
[Tue Mar 26 16:38:49 2013] [warn] [client 78.22.89.200] mod_fcgid: stderr: PHP Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 491520 bytes) in /var/www/dedigitaleboekentas.be/dedigitaleboekentas.be/wwwroot/wp-content/plugins/nextgen-gallery/admin/manage-images.php on line 451, referer: http://dedigitaleboekentas.be.apache08.hostbasket.com/wp-admin/post.php?post=56&action=edit
[Tue Mar 26 16:41:37 2013] [warn] [client 78.22.89.200] mod_fcgid: stderr: PHP Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 491520 bytes) in /var/www/dedigitaleboekentas.be/dedigitaleboekentas.be/wwwroot/wp-content/plugins/nextgen-gallery/admin/manage-images.php on line 451, referer: http://dedigitaleboekentas.be.apache08.hostbasket.com/wp-admin/post.php?post=56&action=edit&message=1

– WordPress up to date: 3.5.1
– NextGEN up to date: 1.9.12
– What version of NextGEN Gallery did you upgrade from: fresh install

– MySQL up to date: 5.0.96
– PHP up to date: 5.2.17
– The mod_rewrite Apache module activated: yes
– PHP Safe Mode OFF: yes

– Who are you hosted with: Hostbasket (Belgium)
– What theme are you running: Avada 2.1.1
– Which plugins do you have installed and activated: NextGen Gallery
– Does this error still occur if you switch your theme to the WP default, and deactivate all plugins except NextGEN Gallery: no

http://wordpress.org/extend/plugins/nextgen-gallery/