.net - RouteUrl And RouteLink Not Working?

I just upgraded to MVC3 final and a part of my site that used to work has totally stopped working. Any idea where my URL's have gone or how to get them back?

Global

routes.MapRoute(
"SingleArticle",
"Articles/{action}/{year}/{month}/{day}/{key}",
new { controller = "Articles", action = "Archive", year = 0, month = 0, day = 0, key = "" },
new { year = @"d{4}", month = @"d{2}", day = @"d{2}" }
);

cshtml

var routeLinkData = new {
action = "Archive",
year = item.PublishDate.Value.Year,
month = item.PublishDate.Value.Month,
day = item.PublishDate.Value.Day,
key = item.NameKey };
URL="@Url.RouteUrl("SingleArticle", routeLinkData)"
Link="<a href="@Url.RouteUrl("SingleArticle", routeLinkData)">Link</a>"

Output

URL=""
Link="<a href="">Link</a>"