Hi,
At first let me tell you one thing, Rounded Edges will not work through css in IE8.
May be your are getting problem because of these code:
border-radius: 5px 5px 5px;
webkit-border-radius: 5px 5px 5px;
-moz-border-radius: 5px 5px 5px;
box-shadow: 0 0 5px 5px #C2C2C2;
-webkit-box-shadow: 0 0 5px 5px #C2C2C2;
-mox-box-shadow: 0 0 5px 5px #C2C2C2;
You just use rounded corner extender of ajax to make it solve.
All the best.
--AK