Web page broken after memory error and cache plugin install

Using Wordpress, Atahualpa theme and NexGen Gallery plugin.
I uploaded some images and got this error...

Fatal error: Out of memory (allocated 53739520) (tried to allocate 16189952 bytes) in /home/bwphoto/public_html/wp-content/plugins/nextgen-gallery/lib/gd.thumbnail.inc.php on line 182

I contacted Hostgator chat and they told me to install WP SUPER CACHE and W3 TOTAL CACHE. The Super Cache was complicated and after install them both my images will not upload and the images I have will not display properly.

Chat told me they could not install these for me and I would have to do it myself. Seems to me that when a host sells you a product they aught to install the plugins to make it functional.

Looks like I have to wipe it all out and start from scratch because most of my posts are getting NO responses from people who might be able to help. I've been using 3 different forums and Wordpress people just do not want to help people.