MVC Actionlink or possible routing issue
<div id="menu-wrapper">
    <div id="menu" class="container">
        <ul>
            <li>@Html.ActionLink("Home", "Index", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.ActionLink("Products", "Products", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.ActionLink("Existing Customers", "Existing", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.ActionLink("Claims", "Claims", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.ActionLink("FAQ", "FAQ", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.ActionLink("Contact Us", "ContactUs", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
        </ul>
    </div>


routes.MapRoute(
"Purchase", // Route name
"Purchase/{AgentId}/{ProductId}/{SchemeId}/{CoverTypeId}/{CoverLevelId/{SubAgentId}",     // URL with parameters
new { controller = "Home", action = "Purchase", AgentId = UrlParameter.Optional, ProductId = UrlParameter.Optional, SchemeId = UrlParameter.Optional, CoverTypeId = UrlParameter.Optional, CoverLevel = UrlParameter.Optional, SubAgent = UrlParameter.Optional } ,  // Parameter defaults
new[] { "BrochureWare.Controllers" }
);

routes.MapRoute(
"Products", // Route name
"Products/{AgentId}/{SubAgentId}", // URL with parameters
new { controller = "Home", action = "Products", AgentId = UrlParameter.Optional,
subAgent = 0 },  // Parameter defaults
new[] { "BrochureWare.Controllers" }
);

        routes.MapRoute(
"MoreInfo_Annual", // Route name
"MoreInfo_Annual/{AgentId}/{SubAgentId}", // URL with parameters
new { controller = "Home", action = "MoreInfo_Annual", AgentId =
UrlParameter.Optional, SubAgent = 0 },  // Parameter defaults
new[] { "BrochureWare.Controllers" }
);

            routes.MapRoute(
"FAQ", // Route name
"FAQ/{AgentId}/{SubAgentId}", // URL with parameters
new { controller = "Home", action = "FAQ", AgentId = UrlParameter.Optional, SubAgent =
0 },  // Parameter defaults
new[] { "BrochureWare.Controllers" }
);

            routes.MapRoute(
"Existing", // Route name
"Existing/{AgentId}/{SubAgentId}", // URL with parameters
new { controller = "Home", action = "Existing", AgentId = UrlParameter.Optional,
SubAgent = 0 },  // Parameter defaults
new[] { "BrochureWare.Controllers" }
);

            routes.MapRoute(
"ContactUs", // Route name
"ContactUs/{AgentId}/{SubAgentId}", // URL with parameters
new { controller = "Home", action = "ContactUs", AgentId = UrlParameter.Optional,
SubAgent = 0 },  // Parameter defaults
new[] { "BrochureWare.Controllers" }
);

            routes.MapRoute(
"Claims", // Route name
"Claims/{AgentId}/{SubAgentId}", // URL with parameters
new { controller = "Home", action = "Claims", AgentId = UrlParameter.Optional,
SubAgent = 0 },  // Parameter defaults
new[] { "BrochureWare.Controllers" }
);

            routes.MapRoute(
"Default", // Route name
"{AgentShortCode}/{referid}", // URL with parameters
new { controller = "Home", action = "Index", AgentShortCode = "Steve", referid = 1
},
// Parameter defaults
new[] { "BrochureWare.Controllers" }
);

<div id="menu-wrapper">
    <div id="menu" class="container">
        <ul>
            <li>@Html.RouteLink("Home", "Default", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.RouteLink("Products", "Products", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.RouteLink("Existing Customers", "Existing", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.RouteLink("Claims", "Claims", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.RouteLink("FAQ", "FAQ", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
            <li>@Html.RouteLink("Contact Us", "ContactUs", new { AgentId = ViewData["AgentId"], SubAgentId = ViewData["ReferId"] })</li>
        </ul>
    </div>