Ok the good news is that I kind of fixed it, the bad one is that I don't know why the change I made fixed it.
I simply put the
(and I think somebody mentioned something like that in this thread) and it works as in the line is now floating left in IE7 as well (yay!!) even if it creates a strange effect on the line itself which looks like it has a secondary smaller line running across the whole width... anyway, why would a
fix it? It is just a container!
What I have done I have replaced
<div id="horizontal_line"> <hr> </div>
This makes no sense at all to me...