Some nil errors with newest modui version. So if you can check it out

http://imgur.com/gxFPx8c

After updating questie, now its good.

Get error again, some arrow lua... in the chat , its not gamebreaking

Ok thanks. I know that WDB isnt a problem, but now I deleted WTF and starting configuring addons again.

Sorry, but we need the error message for us to be able to help.

I'd recommend you install ImprovedErrorFrame. It's an addon that lets you copy&paste the error messages from a window, which you can view using a minimap button (shows only if there were any errors). If there is more than one error, post the first one, the others are probably caused by it.

ImprovedErrorFrame.zip

We need the exact new error message, or at least the line and file (e.g. QuestieTracker.lua:1033 in the screenshot you posted), or we this will be near impossible to fix. Also information on how to reproduce would be welcomed. From your screenshot I guess they happen on login?

Ok thanks , I have that addon but didnt use it yet.
Usually they happen on some time after login.

Same thing happens with addon enemyFrames

A few other things you could try:

1. Delete the Cache (if present) and WDB directories from your World of Warcraft directory. They tend to cause issues upon switching servers (don't worry, this will not delete your settings, they are in the WTF directory).
2. Disable all other addons (or at least enemyFrames) and see if the error still happens. If it does not, some other addon might be responsible.

For reference... line 1033 is: Questie:RedrawNotes() and is used quite often. Trust me, if it were that then you'd have every player complaining about it. EVERY player that uses Questie. :)

If the issue was still happening after clearing out your WDB then it has to be another mod that is causing it.

Ok thanks. Im mot familiar with coding so maybe Im replying too much but I just want to help when I can :D