mkdir(): Permission denied
It's been a while since I was in Craft 2, but I'd suggest checking out this page in the docs:
https://craftcms.com/docs/2.x/folder-structure.html
Do all of the directories mentioned on that page exist on your site? Specifically, I'd confirm that you have the craft/storage folder created in your installation. If it's not there, make it and try to load the page again.