do you get a 'tab mix options' choice when you click on tools? if not, look for the plug-in tab mix plus(i don't know if it's an add-on or if it comes with firefox).
anyway, once you get there, click the display tab, and there's the option to remove the close tab buttons.
What does that have to do with what he asked? He asked if he could get rid of the X on every tab and that thread is about having multiple home pages...