Ok, I was doing Alterac Valley, and my UI had to all but be disabled it was getting so many errors.
I didn't have them when I left AV, though, until I logged in today. This error is very similar to the ones I was getting yesterday in teh BG though, so I will post it:
3x [ADDON_ACTION_BLOCKED] AddOn "nUI" tried to call the protected function "nUI_SoloUnit_Player_Aura2_Button2_HitBox:SetID()".
!BugGrabber-r188\BugGrabber.lua:587: in function <!BugGrabber\BugGrabber.lua:587>
<in C code>
nUI-5.07.29 (Plus)\Units\nUI_UnitAura.lua:326: in function <nUI\Units\nUI_UnitAura.lua:312>
I was getting close to 200 of these similar protected function errors in AV, now I am getting them in Orgrimmar.