"Unified model loading" Null Pointer Exception

Troubleshooting graphics
1

I added the unified model loading class to my code and tried to use it to load a model. My model is in my project's main folder, and I am using Netbeans. I ran it with this line of code:

loadModel("city.3ds")

and I get this error:

Exception in thread "main" java.lang.NullPointerException

        at demoapp.Game.load(Game.java:157)

        at demoapp.Main2.main(Main2.java:22)

Java Result: -805306369



On this line of code in my load model function:

formatConverter.convert(modelURL.openStream(), BO);


I am using jME 2, I hope this is enough information. Thanks in advance.