I cant say I would need to know specifically what the line and character is. I dont have a login so I cant grab your true page source that you see.
test sold - PhotoPost Classifieds
I have viewed my test site classifieds in in 4 different browsers and see no errors with no editor basic editor or the wysiwyg editor.
I would suggest you turn off the display of your header etc or get rid of any other hacks you have made and see if you can reproduce this on a clean install. I would highly suspect a conflict with maybe someone else you have done. Like maybe your menubar coding?