Works fine here. Clear all browser, system, DNS and network device caches and cookies. Try different browsers, etc. If using AVG, get rid of it.
That would certainly make sense. I tried a different browser earlier for that trainer and it worked, but then using that same browser a different one gave me a 404 at the same stage. I usually use Chrome, which seems to be fine now, but if it's sporadic (I'm glad I'm not the only one) than it's most likely what they're doing.