No, that's not the exact error message, I want you to copy and paste what you're seeing and then post it. No offense, but I don't like people's paraphrasing of error messages because quite often it's way off.
It appears either those files weren't on your hd when the patching started, or they were somewhere where the patch program couldn't find them. Are you/were you able to see where those files are sitting on your hard drive? In your war3 folder perhaps?
Have you ever uninstalled/reinstalled the game into a different directory?
This error is coming up because the Mac version of the beta patch isn't available yet. Keep an eye on this forum for an announcement about when it's ready:
Finally finding about some of the bots that are flooding the users online - bytespider apparently is a huge offender here - ignores robots.txt and comes in from a ton of different IPs
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.