At a tournament I was at a player had Auto-Regen on Vet Sabretooth. Sabretooth had no tokens on him. The player rolled for auto-regen and failed. He then used one of his actions to use regular regen. Is this legal? If not please explain why? I figure it has something to do with not being able to use the same power twice in one turn.

Yep, completely legal. He used the Auto Regen as it's described on the feat. He can give Sabertooth an action on his turn... including the power action for Regen (assuming the power is still showing on the dial).

sweet! Thanks hair.

There is no rule that you can't use the same power twice in a turn, but the rule that says you get only on non-free action per turn almost always prevents it from happening. Auto Regeneration is a free action at the beginning of your turn. Since regular regeneration is a power action, the player using both has taken a free action and a power action. Completely legal.

I would suspect he could. One is a free action and one is a power action. I am still double checking but I can't think of anything that states "can only use a power once per turn".

But I am checking.

If The General has Auto-Regen and still has Regen showing after he heals himself can he use Auto-Regen again that turn or only Regen with a power action?

Automatic Regeneration may one be used once at the beginning of the turn. So if the General has already used the feat or if it is no longer the beginning of the turn (maybe the General pushed to get to a Regen click, for example) then the feat may not be used that turn.

If I may toss in a question here... isn't this 'one NON-free action per turn' the reason that a character with Movethrough can knock down a wall (free action) while charging someone (non-free action)?

A character with Movethrough cannot do that. They can target a wall as their allocated attack for the Charge, but that would mean the Charge would be over.
I think you meant Unstoppable though, which lets moving figures make a free close combat attack against blocking terrain during a move action. This however cannot be done during a Charge as Charge is a Power Action rather than a Move Action.

This would be interesting if legal. Because I always thought even with autogen you could only regen once. Out of common sense. Guess I need to reroll for my common sense.

We've always used Auto-Regen this way.