There is another solution to this nagging problem:
In your Quark8-folder "Xtensions" you rename the file SpecialLineBreak.xnt to anything you like, it should however not contain the wording "SpecialLineBreak" (just in order to keep the original) and save it in this folder. Then you load this renamed file into any editor, delete the content, and save the emptied file unter the name SpecialLineBreak.xnt.
When you restart Quark8 you will get a window saying that with this file there something wrong. You tick the little box in the window which offers you not to show this window in the future, then you click on "ignore" (and possibly OK).
After restarting Quark8 the thing is gone for good.
Good luck!
Montanus