I can't add levels, and random errors pop up

[Lunamania]

I really hope I'm doing this right...

"Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 72 bytes) in /home/keepersr/public_html/classes/class_database.php on line 201"

That's all I receive whenever I try to add a level to any of the adoptables on my site. Using chrome, it says the same thing, except it's an error on line 207. I've checked with other computers, and it says the same thing for all of them.

Along with this problem I keep getting "Warning: getimagesize(http://keepersrealm.x10.mx/templates/icons/cog.gif): failed to open stream: operation failed in /home/keepersr/public_html/classes/class_image.php on line 114" and others on every page I go to, all on the same line.

I haven't added/changed anything of the site, besides for the main/basic theme, and I was wondering why it keeps doing this. The errors don't always show, but when they do, there's about 4-5 of them at a time.