Hi,
For my Custom Types I don't use a TitlePart, I implement ITitleAspect. So when creating a new item, it'll crash on this line in AdvancedMenuItemPartDriver.cs
Text = string.Format( "{1}:\t{0}", x.As<TitlePart>().Title, x.ContentItem.TypeDefinition.DisplayName )
Since it'll fail the As conversion.
You should replace that line with.
Text = x.ContentItem.ContentManager.GetItemMetadata( x ).DisplayText,
as noted here by Bertrand
http://orchard.codeplex.com/discussions/311109
Cheers, Sarkie