[Plugin: NextGEN Gallery] thumbnail message

I was just trying to create a thumbnail for an image I uploaded and received the following message.

Can some tell me what this means and what I need to do. Thanks

“Fatal error: Out of memory (allocated 42467328) (tried to allocate 3264 bytes) in /home/lenboy11/public_html/alext/wp-content/plugins/nextgen-gallery/lib/gd.thumbnail.inc.php on line 183”