2
Yea, IE sometimes doesnt play the game when it comes to css and positioning.
In the themes css file look to see how the banner is positioned i.e float, absolute, relative and try and change some values to see if it moves, test in both ff and ie.
As for your centering of the theme with the div wrapped around the entire site try this instead: in the theme html file locate the css rules for body and if if its not already there change it to
#html, body
{
margin:0, auro;
top:0;
left:0;
bottom:0;
right:0;
width:/*your width in pixels i.e 960px*/;
}
this should center the webpage in the browser screen, remember to remove the divs you added.