I am trying to loop through one folder and get the value from a property contained within the fields on a particular document type in a CSHTML file using Umbraco 6. So i used the default code and added a single line which throws an error:

@* Ensure that the Current Page has children, where the property umbracoNaviHide is not True *@
@if (Model.Children.Where("Visible").Any())
{
    @* Get the first page in the children, where the property umbracoNaviHide is not True *@
    var naviLevel = Model.Children.Where("Visible").First().Level;

    @* Add in level for a CSS hook *@
    <ul class="level-@naviLevel">            
        @* For each child page under the root node, where the property umbracoNaviHide is not True *@
        @foreach (var childPage in Model.Children.Where("Visible"))
        {
            <li>
                @{var img = Umbraco.TypedMedia(childPage.GetPropertyValue("imgName"));}
                <a href="@childPage.Url">@childPage.Name + img</a>

                @* if the current page has any children, where the property umbracoNaviHide is not True *@
                @if (childPage.Children.Where("Visible").Any())
                {
                    @* Call our helper to display the children *@
                    @childPages(childPage.Children )
                }
            </li>
        }
    </ul>
}

The error returned at first is The type or namespace name 'TypedMedia' does not exist in the namespace 'Umbraco' (are you missing an assembly reference?)

So i add @inherits umbraco.library at the top of the file and i get the error "no suitable method found to override". Could anyone advise how i am supposed to do this?