unity - "The Object you want to Instantiate is null" But it works, can I ignore the error?

This has never happened to me so I'm a bit confused.

GameObject someObject = Instantiate (Resources.Load ("Prefabs/Items/" + someName)) as GameObject;

This throws an error but the object is actually instantiated and everything works as intended. The error doesn't stop the program no matter how many times I reproduce this.

Can I ignore this error or is there some problem that I'm not seeing?