I just upgraded the ASP.NET Identity Entity Framework package from 1.0 to 2.0 and one of the Ninject bindings is now broken:
kernel.Bind
We added a new base RoleStore class and added the user role entity type as a generic type, so perhaps try
kernel.Bind<IRoleStore<IdentityRole, string>>().To<RoleStore<IdentityRole, string, IdentityUserRole>>();