Do you have to use a PVP char for zaishen challenge ?

I unlocked the zaishen elite island, and a guild member said challenge master rioka gave him a reward. He doesnt have a reward for me but after beating five different teams, the elite island unlocked. Is this because im playing as a PVE character and heys playing a PVP ?

i dont remember an award, i only unlocked the elite island...funny thing was, i did it with one pve player and now all 4 can go...all are pve

You can use the AI battles with both PvE and PvP characters. As long as your PvE character can access the Battle Isles you'll be able to take part in the AI Training grounds.

Once you have unlocked the Elite/Random/Team/etc with 1 character, they are unlocked for all character's - it's an account based unlock.

As for a reward.. no idea. I've gotten up to the Zaishen Challange "Mission" area but thats it. If there is a reward.. I can't say.

How do i beat that zaishen challenge as i use my pve warrior with hench to beat the mesmer team and have done many times yet i still cannot unlock the next challenge. Do i need to beat 5 different teams?

yep, 5 different teams out of the 6 available

I didn't get any award when I made it to the Zaishen Elite. Sure, you talk to the guy and he congratulates you and you can hit accept..it makes the nice little sound like you got experience.

But you don't actually get anything.

*EDIT*

Don't we mean REward? It's not he's gonna give you an olympic gold either..

where are the computer arenas?

Deus Vir - the Ai Arena's are located on the Battle Isles.

To get to battle isles you need to have a PvE character who's can get to Lion's arch or create a PvP only character.

As a PvE character press "M"ap and look for the ship/boat on the map near Lion's Arch. Click that and it will take you to the Battle Isel's.. where you can find the Random Arean's, Team Arena's as well as the AI Training arena's. PvP character's will automatically start in the Battle Isle's.

You get the basic AI Training ground by talking to a NPC called "Master of Paths" on "Isle of the Nameless" (new PvP character's start on this map..). Once you beat 5 AI team's in a row you'll get taken to theZaishen Challange "Mission" area for the next challange.

EDIT

I'm an idiot. You have "Challenge" my reply was thinking it was "Elite", which made your wording wrong.

Carry on.