a little help would be appreciated..(HotU spoilers)

[Locke Da'averan]

long story short: i have 2 problems..

1.Valen won't hit enemies. he runs up to them, gets in his fighting stance but does not attack, at all, ever, it's been like that since i went inside the cave where you have to fight the long death posse.. he just stands there and does nothing, except die when a tougher opponent decides to pummel him..
I've tried to kill/resurrect/have him join and leaving him/have him join and reloading and setting his tactics(and the only thing you can do there is to tell him to guard me) and nothing helps(i haven't tried telling him to stay further away from me, but i don't think that helps..) does anyone know a fix to this?

2.due to previously mentioned conundrum, i can't kill the 3rd keeper(the black slaad). i don't have dispel or anyone that has dispel, but i can get rid of his invisibility, but that creature just won't die, i have a lvl 26 fighter and he can kill anything in seconds usually but this guy has ridiculously high ac and when i do hit him for smth like 50pts, he regens them in no time, i once got him to injured but not further.. so anything that helps me kill that thing is appreciated..