I think that this is a css bug in IE. As you use the "float" property in the style sheet to position stuff alot and that is well documented problem in IE. There are a few workarounds here..
Internet Explorer Float/Margin Bugs
One possible solution might be to add
display: inline;
into the elements that use the float property,
eg
Code:
.right_side {
float : right;
width : 202px;
background : inherit;
overflow : hidden;
display: inline;
}
That might fix it. It might not, but thats just one idea you could try and read other possible workarounds for the float bug in that link I put.