Gun shooting problem (instantiate)

I have a script that worked in one project; however, porting over to another project has been problematic. Basically, I have a fighter with two weapon points on each wing. Firing guns should fire both weapons. This is the code that worked in one project but failed to work in the new project:

		rBulletR = Instantiate(oBullet) as Rigidbody;
		rBulletR.transform.position = oPositionR.transform.position;
		rBulletR.velocity = oShip.transform.TransformDirection(Vector3.forward * (500f + vVelocity));

I’ve only added one gun in the example. The other gun basically has a L instead of R. oPositionR is declared in as a public GameObject with the spawnpoint dragged into the field. oBullet is the bullet rigidbody. And oShip is the actual plane. It is a publicly declared Gameobject with the plane dragged into the field.

The error I get is:

NullReferenceException: Object reference not set to an instance of an object
FireControl.FireGuns () (at Assets/Battlestar Assets/Updated Scripts/FireControl.cs:139)

This code seems ok. Which line is 139? If it’s the second of these lines, maybe oBullet isn’t declared as Rigidbody: typecasting with as returns null if the object can’t be cast to the type, and this would produce the Null Reference Exception when you tried to access its transform.position.