Traditionally, rulings take effect immediately. Because some of these rulings have been well publicized, I suggest that tournament judges the reversal below starting 17 February 2006. This is the same day other errata (e.g., No Victory, Rosoku's Staff) take effect.
;;;;;
Costs: Interfering with a cost will work essentially the same way it did in Diamond Edition.
If all or part of the cost of using an action or bringing a card into play is prevented, or if a cost is increased (e.g., Kaiu Sugimoto (Experienced Keeper of Earth)), the player trying to take the action or play the card may either use further resources to complete the payment or allow the attempt to fail. (This is not negation of efects; the action never occurs at all.) If it fails, the card returns to where it came from or stays where it is (e.g., an announced action card remains in hand; because it is now out of play and face down, it does not count towards the normal once per turn limit or any other usage limits).
The player does not receive a refund on any costs already paid. If the action of attaching a card has its cost interfered with, the same thing happens: the player returns the card being attached to where he played it from and does not receive a refund for any costs paid for it.
Additional: For now, this ruling only concerns effects that change costs after an action is announced. (See here.)
Additional (1 February 2006): Further elaboration.
;;;;;
Underhand of the Emperor: If the first ability successfully causes an attack, you must assign the unit if possible. (No other rulings on this card are changing. In particular, only you can assign the Personality; the controller cannot.) (Reversal.)
;;;;;
Ranged Attacks: The ruling below is being replaced by this one. (1 February 2006)
Castle of the Wasp: Ranged Attacks from action cards cannot be combined (e.g., Guerrilla Tactics), regardless of whether a card in the unit is performing the Ranged Attack. (Reversal.)
Additional: Some card effects that cause other cards to "produce" Ranged Attacks, are being considered. (This consideration resulted in the 1 February post mentioned above.)
;;;;;
Foolish Words: Personalities that were not dishonored can be moved to different battlefields. (Reversal.)