I played my first games according to the Turn Sequence Chart at the end of the rulebook, and interpreted the Combat Phase sequence as players being able to perform action before and after they resolve and declare/resolve enemy attacks and their own attacks, but not in between those steps.
Yet the example for point 1.11 in the Errata 1.1 seems to indicate that I can use actions in between 2 attacks. What am I not getting in the Turn Sequence Chart?
The rule book states that you can play actions between the steps of the combat resolution, too. So if ** represents when players can play actions, it's something like this:
**
combat phase begins, deal shadow cards
**
choose attacker
**
declare defender
**
reveal shadow card(s)
**
resolve combat
**
choose attacker... and so forth.
Oh, does that mean that I can use Daughter of the Nimrodel to heal a hero after he got dealt some additional damge by a shadow effect that would kill him?
Say, I defend with Gimli, he already has 3 damage tokens on him. He defends against a Wargs with a Muck Adder as shadow effect which decreases his defense by one. So I can use DotN after the shadowcard is revealed and before he gets dealt the damage?
If that's the case I have to apologize to Aragorn, Legolas, Gimli and Thalin for letting them die without a need. 
Yep, that's absolutely legal!
I think (and someone please correct me if I am wrong) that the shadow effect is applied before you can take actions. So, if the effect is direct damage that would otherwise kill a character, you can not intervene to save them. However, you can take actions after the effect resolves and before normal combat damage is dealt. So, if defense was lowered you could respond with some kind of action.
You're absolutely correct - but if Gimli survives the damage, you have an action window to heal some of it before the enemy whacks him.
Yeah, in the above example, you would have an opportunity to use the Daughter before Gimli actually took any damage from the attack. If, however, you were in the same situation while playing The Massing at Osgiliath and revealed Wolves from Mordor (Shadow: Deal 2 damage to the defending character), Gimli would be toast unless you had a copy of Hasty Stroke (or Landroval, I suppose).
The round sequence chart at the back of the rulebook gives you a comprehensive idea of when you can and cannot take actions. Any part in green is fair game, even those sections that aren't specifically set aside for player actions.
Hm.. ok... so.. let me ask follow-up questions.
Would that mean that I could
1) ready a defender and have him defend again?
2) ready a defender somewhere in between to use a special ability of his?
3) ready a defender to have him counterattack later?
Yes to all three.