Help making a Fourth Pledge

[Mutant Yoshi]

I've been having trouble creating an Electric Pledge for my game. Whenever I try to use it in conjunction with the other pledges, the game tends to throw an error at me. This is the code I have made:

class PokeBattle_Move_15A < PokeBattle_Move
  def pbOnStartUse(attacker)
    @doubledamage=false; @overridetype=false
    if attacker.effects[PBEffects::FirstPledge]==0x106 ||   # Grass Pledge
       attacker.effects[PBEffects::FirstPledge]==0x107 ||   # Fire Pledge
       attacker.effects[PBEffects::FirstPledge]==0x108      # Water Pledge
      @battle.pbDisplay(_INTL("The two moves have become one! It's a combined move!"))
      @doubledamage=true
      if attacker.effects[PBEffects::FirstPledge]==0x108   # Water Pledge
        @overridetype=true
      end
    end
    return true
  end

  def pbBaseDamage(basedmg,attacker,opponent)
    if @doubledamage
      return basedmg*2
    end
    return basedmg
  end

  def pbModifyType(type,attacker,opponent)
    if @overridetype
      type=getConst(PBTypes,:GRASS) || 0
    end
    return super(type,attacker,opponent)
  end

  def pbEffect(attacker,opponent,hitnum=0,alltargets=nil,showanimation=true)
    if [email protected] || !attacker.pbPartner || attacker.pbPartner.isFainted?
      attacker.effects[PBEffects::FirstPledge]=0
      return super(attacker,opponent,hitnum,alltargets,showanimation)
    end
    # Combined move's effect
    if attacker.effects[PBEffects::FirstPledge]==0x106   # Grass Pledge
      ret=super(attacker,opponent,hitnum,alltargets,showanimation)
      if opponent.damagestate.calcdamage>0
        attacker.pbOpposingSide.effects[PBEffects::ElectricThorns]=4
        if [email protected]?(attacker.index)
          @battle.pbDisplay(_INTL("Electrified thorns surrounded the opposing team!"))
          @battle.pbCommonAnimation("ElectricThornsOpp",nil,nil)
        else
          @battle.pbDisplay(_INTL("Electrified thorns surrounded your team!"))
          @battle.pbCommonAnimation("ElectricThorns",nil,nil)
        end
      end
      attacker.effects[PBEffects::FirstPledge]=0
      return ret
    elsif attacker.effects[PBEffects::FirstPledge]==0x107   # Fire Pledge
      ret=super(attacker,opponent,hitnum,alltargets,showanimation)
      if opponent.damagestate.calcdamage>0
        attacker.pbOwnSide.effects[PBEffects::VolcanicStorm]=4
        if [email protected]?(attacker.index)
          @battle.pbDisplay(_INTL("A volcanic storm occurred on your team's side!"))
          @battle.pbCommonAnimation("VolcanicStorm",nil,nil)
        else
          @battle.pbDisplay(_INTL("A volcanic storm occurred on the opposing team's side!"))
          @battle.pbCommonAnimation("VolcanicOpp",nil,nil)
        end
      end
      attacker.effects[PBEffects::FirstPledge]=0
      return ret
    elsif attacker.effects[PBEffects::FirstPledge]==0x108   # Water Pledge
      ret=super(attacker,opponent,hitnum,alltargets,showanimation)
      if opponent.damagestate.calcdamage>0
        attacker.pbOwnSide.effects[PBEffects::Thunderstorm]=4
        if [email protected]?(attacker.index)
          @battle.pbDisplay(_INTL("A thunderstorm appeared in the sky on the opposing team!"))
          @battle.pbCommonAnimation("ThunderstormOpp",nil,nil)
        else
          @battle.pbDisplay(_INTL("A thunderstorm appeared in the sky on your team!"))
          @battle.pbCommonAnimation("Thunderstorm",nil,nil)
        end
      end
      attacker.effects[PBEffects::FirstPledge]=0
      return ret
    end
    # Set up partner for a combined move
    attacker.effects[PBEffects::FirstPledge]=0
    partnermove=-1
    if @battle.choices[attacker.pbPartner.index][0]==1 # Chose a move
      if !attacker.pbPartner.hasMovedThisRound?
        [email protected][attacker.pbPartner.index][2]
        if move && move.id>0
          [email protected][attacker.pbPartner.index][2].function
        end
      end
    end
    if partnermove==0x106 ||   # Grass Pledge
       partnermove==0x107 ||   # Fire Pledge
       partnermove==0x108      # Water Pledge
      @battle.pbDisplay(_INTL("{1} is waiting for {2}'s move...",attacker.pbThis,attacker.pbPartner.pbThis(true)))
      attacker.pbPartner.effects[PBEffects::FirstPledge]==@function
      attacker.pbPartner.effects[PBEffects::MoveNext]=true
      return 0
    end
    # Use the move on its own
    return super(attacker,opponent,hitnum,alltargets,showanimation)
  end

  def pbShowAnimation(id,attacker,opponent,hitnum=0,alltargets=nil,showanimation=true)
    if @overridetype
      return super(getConst(PBMoves,:GRASSPLEDGE),attacker,opponent,hitnum,alltargets,showanimation)
    end
    return super(id,attacker,opponent,hitnum,alltargets,showanimation)
  end
end

Doing this is really tricky. Also, yes. I've already got Thunderstorm, ElectricThorns, and VolcanicStorm defined in PBEffects.