I managed to slove it eventually:
as for the first error (authsub and google contacts) - I changed the URI from "http" to "https":
// V1
GAuthSubRequestFactory authFactory = new GAuthSubRequestFactory("cp",gn.ytApplicationName);
authFactory.Token = (String)Session["token"];
ContactsService service = new ContactsService(authFactory.ApplicationName);
service.RequestFactory = authFactory;
ContactsQuery query = new ContactsQuery(ContactsQuery.CreateContactsUri("default"));
// VERY IMPORTANT! adding HTTPS resolves google's bug (401 error)
query.Uri = new Uri("https://www.google.com/m8/feeds/contacts/default/full");
ContactsFeed feed = service.Query(query);
about the 2nd error (ClientLogin) - appearantly google have tightened the security measures around this kind of method - they send a warning email to the user that I wanted to log in through - and only if he follows several complex steps they authorize access to his videos.
As I found out this is not an error, but a policy, I think I'll just switch to AuthSub there too.
Hope I could help someone else too...
:)