What version of the arcade are you using and what game, specifically, are you getting this error? I can't test right now as I'm at work (and I'm no longer in an office!) but it will help me when I get home in a few hours.
Sweet! I have a metric f-ton (which is slightly larger than a sh**-load) or games in my public dropbox. But they aren't sorted or anything and they are a major pain. That's really cool of you to offer!
I'm finding that nobody is playing the new games. I think this is because it defaults to the All tab when you first hit the page.
Are we looking at doing something where they see 2 columns - top games and new games?
There's your problem right there. You need to make sure the frontend & function files are loaded onto your server correctly. I get the ugly error, too, so I don't think it's a problem.
Put those two files in and I'll bet everything works.
Okay, first things first:
XF version you are using.
XF Arcade version you are using.
Have you done a file health check?
Are all of your templates updated?
What addons do you have installed?