Make sure you run TB as administrator. Make sure your TB folder isn't set to read-only. Try using steam version if you use stand-alone, or using the stand-alone if you're using steam. Consider doing a reinstall. Afterwards if it doesn't help check these faq threads:
http://forum.toribash.com/showthread.php?t=455410
http://forum.toribash.com/showthread.php?t=214209
If all else fails, consider trying a VPN.