Netflix has always had really poor “second user under this account” support. Certain things just don’t ever work, like logging in, deleting profiles, or adding friends, for example.
Unfortunately, Netflix provides the same problem as Amazon does: They’re still the best out there for what they do, by a large enough margin that it’s not really worth considering the alternatives. Shame.
So, I’ve split up my queue and made a separate account, since they will never allow themselves to be bothered and actually fix the damn thing.
In the next few days I’ll get stuff moved over, though I’ll lose several hundred films worth of rating information. Will try to re-establish connection with Netflix friends; my address should be the same as before.