Make a spawned in prefab child of object.

So I have a jetpack upgrade in which if you clikc a button a jetpack will spawn and you can fly with it. I already have a script inplace to spawn in the jetpack and to change the players behaviour i just run into issues when i try to spawn in the sprite of the jetpack. So here is my code:

function jetpackon ()
	if( >= 50)
		var jetpacksprite : GameObject;
		jetpackbought = true;
		var jetpackposition = target.position;
		var TempSpawnjetpack = Instantiate (jetpacksprite,jetpackposition, Quaternion.identity);
		jetpacksprite.transform.parent = transform; = -50;

In the scene I have a prefab with the jetpack sprite in it and i placed it in the slot of my player as jetpacksprite. Now the jetpack spawns in but it doesnt follow the player and i get this error code:
“Setting the parent of a transform which resides in a prefab is disabled to prevent data corruption.
Not sure how else i should do this so i thought i would ask it here. If you guys could just tell me what i am doing wrong that would be great. Thank you for reading this :3

TempSpawnjetpack.transform.parent = transform