any body can help out with these questions about game mechanics?

1)when monster hit die is referred to, on what kind of die is it? d10?
2)many spells have saving throw. for any particular spell where a saving throw is involved, what do you actually mean when you say save at -2? what are the numbers involved? and if the saving throw succeeds, does it mean that the spell is totally negated or it depends on the spell? and is the magical resistance the second test a spell must pass?
3)finally, something i still can't figure out...what actually immunises against stun!!!

thanks a bunch

1) Never figured that out, sorry.
2) When a saving throw is made, a D20 is rolled. Every creature has a certain saving roll for each of five different situations. Say you use a finger of death against a dwarven battlerager who has a saving roll vs. death of 8. He rolls a D20 and scores a 9, and doesn't die. If he had scored anything below an 8, he would have died. If a saving throw is made at a penalty of -2, it means that if the dwarf rolled a 9, his score would be 9 - 2 : 7, and he would die.
3) Doesn't chaotic commands immunise against stun?

If i don´t remember wrong a creatures hit die is a D8.

1) When I used to play pen and paper AD&D the hit dice of a monster was always calculated with a d8 die. I assume that because this game follows AD&D rules, this still applies.
2) As Armisael's reply
3) I think that any mind defence/warding spell or item gives defence against Stun

Thanks guys

but i really don't know about the stun thing cos my 2nd toughest battle was actually against Balor of underdark fame and the reason is cos his stun cannot be counteracted no matter if i used chaotic commands. or is that creature the only exception? hmmm..

I dunno, but I too found Balor a little unusual... he's not that hard, but you have to hit him real hard real fast before he stuns/holds/fears the entire party. I may be wrong but it seems he's somewhat special in this sense. Know too little about the rules to find out what though.

2)I did a few test for a while ago, I casted "finger of death" at my monk with
high magic resistance(about 80%), and he is almost immune to the spell(I tried 15 times, and every time
he was resistant to the spell), later I tried this on Viconia, and she has also great magic resistance,
but she died finally of the spell after I tried 10 or more on her.
so I think the magic resistance is measured or calculated fisrt, and secondly the
saving throw is made if the M_R is failed.

On the question re: stun, the only thing that can influence this is magic resistance. If your hp is less than 90 you will be affected by it, that's why it's such a great spell and that's why Celestial Fury is such a great weapon. Just hammer anything till you guess their hp drops below 90 and then cast it.

Balor is actually one of the most powerful tanar'ri around. Interestingly enough, as a joke i summoned a glabrezu and a pit fiend and had them fight, the pit fiend lost every time as the glabrezu were immune to all of his attacks and the pit fiend wasn't immune to the glabrezu's attacks. Pit fiends are actually devils, not demons.

The reason Balor's stun attack isn't affected by chaotic commands (unlike the mind flayers' psionic abilities or the stun spells) is a little complicated. I'm pretty sure chaotic commands only provides immunity to those certain spells that stun you, not the entire opcode for stun itself, so if Balor or the celestial fury hits you, chaotic commands won't help.

Huh? I always thought one of the things Free Action helps you with is stun...

Free Action assists with spells that inhibit movement such as web, hold person etc. Stun is a Power Word and there are no saves/immunities to Power Words AFAIK except for natural magical resistance. I'm assuming that CF has the same Stun effect as Power Word Stun. Chaotic Commands won't work against stun because Stun doesn't affect your mind.

S'got a stupid status effect icon, then. : P
So in that case, how does chaotic commands make you immune to psionics? I know there's no separate opcode for them.

The 3rd lvl cleric spell "remove paralyse" will remove the stun effects. Aside from that I know of no defense short of magic restistance( to be redundant) and items that provide immunity.