Check your web.config file. You should add missing namespaces like this:
<namespaces>
<add namespace="System.Web.Mvc" />
<add namespace="System.Web.Mvc.Ajax" />
<add namespace="System.Web.Mvc.Html" />
<add namespace="System.Web.Routing" />
<add namespace="System.Web.Optimization" />
<add namespace="Kendo.Mvc.UI" />
</namespaces>