Errors while using custom dependency resolver with Unity and Web API controller

I am using following class as a dependency resolver. Got reference from http://www.asp.net/web-api/overview/advanced/dependency-injection

   public class UnityWebAPIResolver : IDependencyResolver
    {
    protected IUnityContainer container;

    public UnityWebAPIResolver(IUnityContainer container)
    {
        if (container == null)
        {
            throw new ArgumentNullException("container");
        }
        this.container = container;
    }

    public object GetService(Type serviceType)
    {
        try
        {
            return container.Resolve(serviceType); **// This line throws error**
        }
        catch (ResolutionFailedException)
        {
            return null;
        }
    }

    public IEnumerable<object> GetServices(Type serviceType)
    {
        try
        {
            return container.ResolveAll(serviceType); **// This line throws error**
        }
        catch (ResolutionFailedException)
        {
            return new List<object>();
        }
    }

    public IDependencyScope BeginScope()
    {
        var child = container.CreateChildContainer();
        return new UnityWebAPIResolver(child);
    }

    public void Dispose()
    {
        container.Dispose();
    }
}

In WebApiConfig class after route configuration i am configuring dependency resolver like this

config.DependencyResolver = new UnityWebAPIResolver(UnityConfig.GetContainer());

The problem is i am getting several errors like this..

InvalidOperationException - The type IHostBufferPolicySelector does not have an accessible constructor.
InvalidOperationException - The type ModelMetadataProvider does not have an accessible constructor.
InvalidOperationException - The type ITraceManager does not have an accessible constructor.
InvalidOperationException - The type ITraceWriter does not have an accessible constructor.
InvalidOperationException - The type IHttpControllerSelector does not have an accessible constructor.
InvalidOperationException - The type IAssembliesResolver does not have an accessible constructor.
InvalidOperationException - The type IHttpControllerTypeResolver does not have an accessible constructor.
InvalidOperationException - The type IHttpActionSelector does not have an accessible constructor.
InvalidOperationException - The type IActionValueBinder does not have an accessible constructor.
InvalidOperationException - The type IContentNegotiator does not have an accessible constructor.
InvalidOperationException - The type IHttpControllerActivator does not have an accessible constructor.
InvalidOperationException - The type IBodyModelValidator does not have an accessible constructor.

Even if i try to do something like this in my global.asax i am getting same errors.

GlobalConfiguration.Configuration.DependencyResolver = new UnityWebAPIResolver(UnityConfig.GetContainer());

Question : All dependencies into my API Controller seems to be injected properly, my only concern is since it cannot resolve several of above mentioned (framework specific ) types, is there any chance that it can cause the whole framework malfunction and generate random errors ?