CSS background problem i Firefox

Hej Alle,

Jeg har et lille problem, jeg har en menu i CSS hvor jeg benytter et baggrundsbillede.. Dette billede bliver ikke vist i Firefox, men i IE, vises det rigtigt..

Er der nogen der kan hjælpe med dette problem.. CSS koden, ses nedenfor..

/* Left Navigation Menu */
.leftnav {
  font-family: Verdana, Arial, Helvetica, sans-serif;
  font-size: 14px;
  color: #682809;
  background-attachment: fixed;
  background-image: url(images/menuback.gif);
  background-repeat: no-repeat;
  background-position: left center;
  height: 23px;
  width:125px;
  line-height:23px;
  text-indent: 22px;
}
.leftnav a:link {
  font-family: Verdana, Arial, Helvetica, sans-serif;
  text-decoration: none;
  color: #000000;
  display: block;
}
.leftnav a:visited {
font-family: Verdana, Arial, Helvetica, sans-serif;
  text-decoration: none;
  color: #000000;
  display: block;
}
.leftnav a:active {
font-family: Verdana, Arial, Helvetica, sans-serif;
  text-decoration: none;
  color: #000000;
  display: block;
  background-attachment: fixed;
  background-image: url(images/menuback.gif);
  background-repeat: no-repeat;
  background-position: left center;
}
.leftnav a:hover {
font-family: Verdana, Arial, Helvetica, sans-serif;
  text-decoration: none;
  color: #000000;
  display: block;
  background-attachment: fixed;
  background-image: url(images/menuback.gif);
  background-repeat: no-repeat;
  background-position: left center;
}

.leftnav_act {
  font-family: Verdana, Arial, Helvetica, sans-serif;
  font-size: 14px;
  color: #682809;
  background-attachment: fixed;
  background-image: url(images/menuback.gif);
  background-repeat: no-repeat;
  background-position: left center;
  height: 23px;
  width:125px;
  line-height:23px;
  text-indent: 22px;
}
.leftnav_act a:link {
font-family: Verdana, Arial, Helvetica, sans-serif;
  text-decoration: none;
  color: #000000; 
  display: block;
}

.leftnav_act a:visited {
font-family: Verdana, Arial, Helvetica, sans-serif;
  text-decoration: none;
  color: #000000;
  display: block;
}

På forhånd tak..