CMB = Base attack bonus + Strength modifier + special size modifier.

and

When you attempt to perform a combat maneuver, make an attack roll and add your CMB in place of your normal attack bonus. Add any bonuses you currently have on attack rolls due to spells, feats, and other effects. These bonuses must be applicable to the weapon or attack used to perform the maneuver.

So...

1) if someone tries to DISARM using 2 weapons does he get the normal -2 attack roll penalty to his CMB? The above two paragraphs dont mention anything about two weapon penalties. (I could ask the same for a TRIP attemp but i think its the same with DISARM).

2) if you wield a magic weapon or just a mwk one, you dont get any bonuses, right?

1) if someone tries to DISARM using 2 weapons does he get the normal -2 attack roll penalty to his CMB? The above two paragraphs dont mention anything about two weapon penalties. (I could ask the same for a TRIP attemp but i think its the same with DISARM).

If you wield a second weapon in your off hand, you can get one extra attack per round with that weapon. You suffer a –6 penalty with your regular attack or attacks with your primary hand and a –10 penalty to the attack with your off hand when you fight this way. You can reduce these penalties in two ways. First, if your off-hand weapon is light, the penalties are reduced by 2 each. An unarmed strike is always considered light. Second, the Two-Weapon Fighting feat lessens the primary hand penalty by 2, and the off-hand penalty by 6.

2) if you wield a magic weapon or just a mwk one, you dont get any bonuses, right?
A magic weapon is enhanced to strike more truly and deliver more damage. Magic weapons have enhancement bonuses ranging from +1 to +5. They apply these bonuses to both attack and damage rolls when used in combat. All magic weapons are also masterwork weapons, but their masterwork bonuses on attack rolls do not stack with their enhancement bonuses on attack rolls.

so No it does not add to CMB

I still do not understand why i get penalties for two weapon fighting while tring to disarm.
Lets say i have BAB for only one attack with the main weapon. But i also use one more weapon in my off hand.
I ll mention again that CMB = Base attack bonus + Strength modifier + special size modifier.
So why do i get a penalty if i use two weapons to attemp a disarm action? According to the bolted sentence above i can make disarm attacks in the place of melee attacks (2 attacks in my example) and i should not take any penalty because i have to use only BAB + STR + SIZE.

"Add any bonuses you currently have on attack rolls due to spells, feats, and other effects."

That should probably read "modifiers", not just bonuses, but you get the idea.
The same line also means weapon enhancements DO apply, at least for maneuvers using said weapon.

Because it's an attack action and dual wielding imposes it's penalty whether you use both weapons or not.

"Add any bonuses you currently have on attack rolls due to spells, feats, and other effects."

That should probably read "modifiers", not just bonuses, but you get the idea.
And the same line also means weapon enhancements DO apply, at least for maneuvers using the weapon.

And again, the rule talks about spells+feats+effects only. It doesnt talk about various combat modifiers (e.g. the two weapon fighting penalty). Should i include it to the various "effects" too?

The rule was clear at 3.5E but now it confuses me. Is there any errata?

Because it's an attack action and dual wielding imposes it's penalty whether you use both weapons or not.

Well if weapon enhancments apply then why not the masterwork quallty? Are those two included to the "effects"?

And again, the rule talks about spells+feats+effects only. It doesnt talk about various combat modifiers (e.g. the two weapon fighting penalty). Should i include it to the various "effects" too?

Because it's an attack action...

Well simply because weapon quality was not listed as something that affects the CMB. Now was this an oversight?
Is this purposeful?
Well Jason would have to answer that one.
I would say discuss it with the GM and then make a decision. Personally I think there should be a separate quality for enchanting weapons that adds to CMB. But that is just me.

1) if someone tries to DISARM using 2 weapons does he get the normal -2 attack roll penalty to his CMB?

2) if you wield a magic weapon or just a mwk one, you dont get any bonuses, right?

2) You gain the enhancement bonus from either.

Both of these require you use the weapon to perform the disarm.