Locked out of dashboard

I am unable to log into the dashboard for my website. When I try, I get a page of lines saying:
Warning: Creating default object from empty value in /home/hundreds/hundredsofhundreds.com/wp-content/themes/platformpro/core/library/class.layout.php on line 159 (and line 162, etc)

I have not posted to my wordpress site in a while, but keep it reasonably updated and haven’t made any changes or deleted any important files that I am aware of. The spam filter is not working now and the spam comments are pouring in. Any help much appreciated!

https://www.hundredsofhundreds.com