Try deleting the thorui folder and letting the thorui AU redownload all the thorui files fresh.
Also check to see if you have my quest journal selected.
It should have a title of "ThorUI Quest Journal"
If you still have trouble after doing the above let me know and we'll see what we can track the issue down to.
You can also look in your Sony\EverQuest II directory and see if you have a "ui.log" and look at it.
This will list issues with UI pieces. (Yes it lists issues with SOE's default as well)