padding or margin wrong or both

padding or margin wrong or both

I tried something with divs in html, and normally it isn't a problem.
However I encountered a problem and I don't find my mistake.
The menu div is supposed to be in the center of the header div and there
should be no margin at the top.
here is the example with the error: http://jsfiddle.net/j83eb/
here is the html:
<div id="header">
<div id="menu">
<ul>
<li><a class="nav-element" href="#">News</a></li>
<li><a class="nav-element" href="#">Turnier</a></li>
<li><a class="nav-element" href="#">Ergebnisse</a></li>
<li><a class="nav-element" href="#">Impressionen</a></li>
<li><a class="nav-element" href="#">Anmeldung</a></li>
<li><a class="nav-element" href="#">Impressum</a></li>
</ul>
</div>
</div>
and the css:
#header {
padding: 0;
margin:0;
background: #003399;
width: 100%;
height: 50px;
display: block;
position: fixed;
top: 0;
left: 0;
}
#menu a {
display: block;
width: 150px;
height: 50px;
}
#menu {
padding:0;
margin-right:auto;
margin-left:auto;
line-height:50px;
width: 950px;
height: 50px;
}
#menu ul li {
display: block;
width: 150px;
height: 50px;
float: left;
text-align: center;
text-transform: uppercase;
font-family: Arial;
font-size: 16px;
font-weight: normal;
list-style: none;
margin:0;
paddin:0;
line-height:50px;
}
.nav-element:link {
color: #FFF;
text-decoration: none;
}
.nav-element:visited {
color: #FFF;
text-decoration: none;
background: #81b4e3;
}
.nav-element:hover {
text-decoration: none;
color: #FFF;
text-decoration: none;
background: #1a589d;
}
.nav-element:active {
color: #FFF;
text-decoration: none;
background: #C00;
}
Thanks!