Feste Menübreite funktioniert nicht - eine zweite Zeile unterbinden

<div class="header-top">        
        <!-- Navigation Level 1 -->
        <div class="nav1">
          <ul>
            <li><a href="#" title="Send us a message">Kontakt</a></li>                                
          </ul> 
          <ul>  
            <li><a href="#" title="Send us a message">International</a>
              <ul>
                <li><a href="#" title="English">English</a></li>
                <li><a href="#" title="Deutsch">Deutsch</a></li>
                <li><a href="#" title="Francais">Fran&ccedil;ais</a></li>
                <li><a href="#" title="Italiano">Italiano</a></li>
              </ul>
            </li>
          </ul>
          <ul>
            <li><a href="#" title="Who we are">Sitemap</a></li>
          </ul>
          <ul>  
            <li><a href="#" title="Send us a message">Impressum</a></li>
          </ul>                                             
        </div>
        <!-- Search form -->                  
        <div class="searchform">
          <form action="index.html" method="get">
            <fieldset>
              <input name="field" class="field"  value=" Search..." />
              <input type="submit" name="button" class="button" value="GO!" />
            </fieldset>
          </form>
        </div> 
        <!-- A.3 HEADER BOTTOM -->
        <div class="header-bottom">

        <!-- Navigation Level 2 (Drop-down menus) -->
        <div class="nav2">
        <ul>
             <!-- Navigation item -->
            <li class="design_eins"><a href="index.html">Ein sehr langer Menutitel</a></li>
            <li class="design_zwei"><a href="#">Ein sehr langer Menutitel 1</a></li>
            <li class="design_drei"><a href="#">Ein sehr langer Menutitel 2</a></li>
            <li class="design_vier"><a href="#">Ein sehr langer Menutitel 3</a></li>
            <li class="design_fuenf"><a href="#">Ein sehr langer Menutitel 4</a></li>
        </ul>                              
        </div>
      </div>           
      </div>

/*Drop-down menu*/
.nav2 {margin:1.5em 0 0 0; white-space:nowrap /*IE hack*/; float:left;   width:954px; color:rgb(255,255,255); font-size:120%;} /*Color  navigation  bar normal mode*/
.nav2 ul { list-style-type:none;}
.nav2 ul li {float:left; z-index:auto !important /*Non-IE6*/; z-index:1000 /*IE6*/; border-right:solid 1px rgb(255,255,255);}
.nav2 ul li a {float:none !important /*Non-IE6*/; float:left /*IE-6*/;   display:block; padding:0 16px 0 16px; text-decoration:none;   font-weight:normal; color: rgb(255,255,255);}
.nav2 ul li ul {display:none; border:none;}


.design_eins {background-color:rgb(51,103,153);}
.design_zwei {background-color:rgb(159,0,95);}
.design_drei {background-color:rgb(5,132,113);}
.design_vier {background-color:rgb(173,10,15);}
.design_fuenf {background-color:rgb(231,169,34);}


/*Non-IE6 hovering*/
.nav2 ul li:hover {position:relative;} /*Sylvain IE hack*/
.nav2 ul li:hover a {background-color:rgb(218,222,226);   text-decoration:none; color:rgb(80,80,80);} /*Color main cells hovering   mode*/
.nav2 ul li:hover ul {display:block; width:10.0em; position:absolute; z-index:999; top:2.0em; margin-top:0.1em; left:0;}
.nav2 ul li:hover ul li a {white-space:normal; display:block;   width:10.0em; height:auto; line-height:1.3em; margin-left:-1px;   padding:4px 16px 4px 16px; border-left:solid 1px rgb(175,175,175);   border-bottom: solid 1px rgb(175,175,175);   background-color:rgb(240,240,240); font-weight:normal;   color:rgb(80,80,80);} /*Color subcells normal mode*/
.nav2 ul li:hover ul li a:hover {background-color:rgb(218,222,226); text-decoration:none;} /*Color subcells hovering mode*/


/*IE6 hovering*/
.nav2 table {position:absolute; top:0; left:-1px; border-collapse:collapse;}
.nav2 ul li a:hover {position:relative /*Sylvain IE hack*/; z-index:1000   /*Sylvain IE hack*/; background-color:rgb(218,222,226);   text-decoration:none;color:rgb(80,80,80);} /*Color main cells hovering   mode*/
.nav2 ul li a:hover ul {display:block; width:10.0em; position:absolute;   z-index:999; top:2.1em; t\op:2.0em; left:0; marg\in-top:0.1em;}
.nav2 ul li a:hover ul li a {white-space:normal; display:block;   w\idth:10.0em; height:1px; line-height:1.3em; padding:4px 16px 4px  16px;  border-left:solid 1px rgb(175,175,175); border-bottom: solid 1px   rgb(175,175,175); background-color:rgb(218,222,226);  font-weight:normal;  color:rgb(80,80,80);} /*Color subcells normal  mode*/
.nav2 ul li a:hover ul li a:hover {background-color:rgb(218,222,226); text-decoration:none;} /*Color subcells hovering mode*/