This is a BIG one and its hitting about everyone.
Delete the contents of your Cache folder every time you log in until it is fixed. The error will look something like this:
Error #134 (0x85100086)
blahblahblah
Duplicate 'unique key' 211489 found ID blahblah in DBfilesClient\PVPTalent.db2
Probably something to do with those of us who have PVPed since the patch and gotten the achievement for the first ability even though the system is open yet...just my guess :)
So yeah, go into your Program Files, find your WoW stuff and find the Cache Folder. Do not delete the actual folder, just everything inside.