Css code problem in firefox and safari

Hi I have a problem with my website:

www.longcroft.eriding.net

the banner at the top is not displaying correctly in firefox and safari, the css code is below, does anybody have any ideas its aligning to the left not the centre. It works fine in ie
Thanks

#banner {
background-color: white;
text-align: center;
padding: 0px;
margin: 0px;
}
#banner img {padding:0px 0px;}

try this

#banner {
background-color: white;
text-align: center;
padding: 0px;
margin: 0px;
}

#banner img {padding:0px 0px;
width: (enter the width of the banner - important )
margin:auto;
}


this should center the image.