Are there any attackchoppers that can operate from a carrier or LHD?
If so, wich?

im not completely sure but the U.S's super cobra must be able to,
and also one form of the apache (i think italian) can operate from carrier.

the british lynx is both an attack helicopter and a navy helicopter but im not sure if the attack helicopter varient can work on a carrier.

hope this helps

Only the Marine Corps AH-1 Super Cobra is capable of shipboard operations.

Are there Marine Apaches or Blackhawks capable of naval operations?

The Seahawk is the Navy version of the Black Hawk.
I can't see why the Apache couldn't be put on the deck of a ship.

yes of course, but I do not think the navy has any attack choppers in the field unless you count the anti submarine warfare

the British SeaKing can attack subs, but is mainly a search and rescue chopper

almost all british choppers can server onboard a ship though: SeaKing,Lynx,Puma,Chinook,Gazelle

I can't see why the Apache couldn't be put on the deck of a ship

I have heard that the apache cant stand (salt/sea) water. Besides that, the apache hasn't got a landing gear strong enough to land on a unstable ship. So I have heard.

Well those are easy modifications.
How is it that a Cobra won't have much problems but an Apache would go nuts?

How is it that a Cobra won't have much problems but an Apache would go nuts?

It probally has got something to do with the design. For example: there is the blackhawk, but the navy has got the seahawk. Just like the new NH-90. You have the tactical version and the naval version. What the exact difference is, i dont know. But there has to be, because designing a different version of a chopper for a navy seems to be unnecessary work if any chopper could operate at sea with ease. Right?