Css

This is what I have been staring at the last hours. I just doesn't understand what I am doing wrong, my page seems to flip the layout without reason. Just sometimes. When I have reloaded so many times that I think everything is ok.

Gahh..

#header {
height: 150px;
background: transparent url(../images/header_bg.jpg) top center no-repeat;
margin: 10px auto 0 auto;
width: 940px;
padding: 0;
}


#header_main .hleft {
float: left;
width: 474px;
height: 276px;
background: transparent url(../images/header_cinelogo.png) top left no-repeat;
padding: 0;
}

#header_main .hright {
float: left;
width: 466px;
height: 256px;
padding: 10px 0 0 10px;
}

#header_main .hright .hwr-left {
float: left;
width: 228px;
}

#header_main .hright .hwr-right {
float: right;
width: 228px;


Oh well.

Gotta have a break now.
See ya later alligator.