The text on warworld is kinda confusing for me. Does this mean my opponent can get the effect from it too?

Also, can someone give me a link for the errata?

Yes Warworld's effect works for all players.

Warworld
Location, 3
Flip Warworld only if you control a Revenge Squad character.
While attacking a character, if an attacker would cause breakthrough to a player, that player loses endurance equal to that attacker’s cost instead.
[OCR 10 Feb 05]

The latest Official Card Reference can always be found here.

An easy to remember URL for the location is: http://www.ude.com/rules

Wow, I didn't notice that before... ^_^ Interesting... FatBat defense, and it can stifle Bastion some as well.