Well some how I'm not getting this error, and you guys are. I even rolled back my local version to beta4 just to be sure, no dice.
So Ordrosh and Moodib, do this:
Get to an area where you can get this error, then start logging by entering
into chat. Do whatever it is you're doing to get the error, then type
to stop logging.
Then go to World of Warcraft Beta\Logs, upload the taint.log file to your favorite file sharing site, and PM me the link.