what is the correct way to remove a newton gravity entity?

when i use ent_remove(me) at an entity i get this error:

Code:

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 Error E1515   
 Invalid arguments in NewtonMaterialGetSoundEffect: ENT_playSOUND(my,sound,volume)

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i use this as script for my entity:
Code:

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function move_grenade(){
	var collisionType = 0;
	
	var body;
	body = NewtonAddMapEntity (my, collisionType);
	
	NewtonSetBodyMass (body, 1);
	NewtonSetBodyLinearDamp (body, 0.1);
	NewtonSetBodyAngularDamp (body, 0.3, 0.3, 0.1);
	NewtonSetBodyForceAndTorque (body, ApplyGravityForceEvent);
	NewtonSetBodyMaterial (body, wood_material);
	NewtonSetBodyActiveState (body, 1);
	NewtonSetBodyAutoActiveState (body, 1);
	
	newtonImpulseRecord[0]=player.x;
	newtonImpulseRecord[1]=player.y;
	newtonImpulseRecord[2]=player.z;
	
	newtonImpulseRecord[3]=player.x; 
	newtonImpulseRecord[4]=player.y;
	newtonImpulseRecord[5]=player.z - 100;
	
	
	newtonImpulseRecord[6]=1;
	
	
	newtonImpulseRecord[7]=8000;
	
	NewtonBodyAddImpulse(NewtonGetBody(me),newtonImpulseRecord);
	
	sleep(2);
	
			ent_create(explosion,my.pos,genade_explode);
			ent_remove(me);
}

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