Yellow Bars
 

I updated the AddOn for the version 5.1 of the game and the action bars look yellow.



Reguards.

That looks like missing textures.

Did you fully exit the game client?
If there's new files added the game will not recognize them until it's fully exited and restarted.

Re-install
 

Your textures/meshes look a little funky. Try re-installing it manually and see if you get the same problem. You shouldn't though re-install will most likely fix it.

- Cheers

On a side note, that's lime green—not yellow. You may want to look into calibrating your monitor if it appears yellow.

I think confusing green with yellow just means he's colorblind and it's actually indistinguishable from yellow. :p