I think Dan was close with his answer, but this is not a specific issue. You can set the list style in a list (UL), but you can also override this list style for individual list items (LI).
You tell the browser that it does not use bullets in the list, but the YUI tells the browser to use them in separate elements of the list (YUI wins):
ul li{ list-style: disc outside; }
#nav ul.links {
list-style: none;
}
, :
ul li{ list-style: disc outside; }
#nav ul.links li {
list-style: none;
}