Mein Script funktioniert mittlerweile, hab vor der abfrage vom target ein If Possible == 0 gehängt:
Code: 
Scriptname ZFinisherQuestScript

Short Done

Float fQuestdelayTime;set to 0.1 from another script

Short Finisherkey

Ref PossibleTarget
Ref Target

Ref PlayerWeapon
Ref PlayerWeaponType

Short Move
Short Possible

Float Timer

Short TargetBaseHealth

Begin GameMode
	If IsKeyPressed2 Finisherkey
		Set Move to 1
	Endif
	If Move == 1
		if Possible == 0
			Set PossibleTarget to GetCrosshairRef
			If PossibleTarget != 0
				If ( PossibleTarget.IsActor ) 
					If ( PossibleTarget.IsCreature == 0 ) 
						If ( PossibleTarget.GetDead == 0 )        
							Set Target to PossibleTarget
							Set Possible to 1
						Endif
					Endif
				Endif
			Else
				Set move to 0
			Endif
		ElseIf Possible == 1
			Set Playerweapon to Player.GetEquippedObject 16
			If PlayerWeapon != 0
				Set PlayerWeaponType to GetWeaponType PlayerWeapon
			Endif
			Set TargetBaseHealth to Target.GetBaseActorValue Health
			If Player.IsWeaponOut
				If PlayerWeaponType == 0 || PlayerWeaponType == 1
					If Target.GetAV Health <= (TargetBaseHealth / 2)
						If Player != Target
							;If Target.GetDistance Player <= 120
								Player.SetRestrained 1
								Target.AddItem ZTFinisherRing 1
								Set Possible to 2
								Player.Pickidle
								Target.PickIdle
								Set Possible to 3
							;Else
								;Set Move to 0
							;Endif
						Else
							Set move to 0
						Endif
					Else
						Set Move to 0
					Endif
				Else
					Set move to 0
				Endif
			Else
				Set move to 0
			Endif
		Elseif Possible == 3
			If Timer >= 1                   
				Target.Kill
				Target.RemoveItem ZTFinisherRing 1
				Player.SetGhost 0
				Player.SetRestrained 0
				Set Move to 0
				Set Timer to 0
				Set Possible to 0
			Endif
			Set Timer to Timer + GetSecondsPassed
		Endif
	Endif
End
Die im offiziellen Forum meinen auch das die abrfragen (IsActor, IsCreature) nacheinander gemacht werden sollten.

Jedenfalls klappt das jetzt danke, werd später wenn ich soweit bin vllt nochmal auf Pluggy zurückkommen und könnt da noch Hilfe gebrauchen.
Lg