Yeah, I've downloaded the most recent version, 1.7. I'll try redownloading it to see if that helps.
Yep, it works completely fine now. Guess it was just a problem with the download.
I've tried playing the game, and it's likely from a lack of knowledge/experience, but I keep getting this error message. I've unzipped the main game and resource pack, but haven't done anything to them further. Does anybody know what's going on?