IUnityContainer.Resolve throws error claiming it cannot be used with type parameters

I had the same problem and found the “fix” looking at Prism sample code files. Looks like, even if it is not a dll in Unity V2 you have to add a reference in your class to:
Microsoft.Practices.Unity

my complete “using” section is as follow

using System;
using System.Windows;
using Microsoft.Practices.Composite.Modularity;
using Microsoft.Practices.Unity;
using Microsoft.Practices.Composite.UnityExtensions;

I’m not sure if you are using Silverlight, but the generic version for Container.Resolve IS in Microsoft.Practices.Unity.