Hey everybody. I'm new to forum making. I tried to install a template for phpbb's following a tutorial, and I was logged in as the admin and switched to that style to see if it worked. Well it didn't work, and now I can't do anything..this is what it's saying now

phpBB : Critical Error

Could not open o7media template config file

DEBUG MODE

Line : 503
File : functions.php


I can't do anything now. I deleted the template out of my host, so now there's only subsilver (the default one) left. But it didn't help


Can someone help please??