Can't update inventory on an item

Hello:

I am trying to update the inventory on an item using a Web Service call.
When I try to do so, I get this error back from the call:

You must specify a valid line ID.  Please set locationId.

Here is my test code:

RecordRef locationRef = new RecordRef();
            locationRef.setInternalId("1");
            locationRef.setType(RecordType.location);
            InventoryItemLocations updateLocations = new InventoryItemLocations();
            updateLocations.setLocationId(locationRef);
            updateLocations.setQuantityAvailable(25.0);
            InventoryItemLocationsList updateLocationsList = new InventoryItemLocationsList();
            updateLocationsList.setLocations(new InventoryItemLocations[] {updateLocations});
            InventoryItem updateItem = new InventoryItem();
            updateItem.setInternalId("199");
            updateItem.setLocationsList(locationsList);
            NetsuiteUtil.getInstance().update(updateItem,null,null);

As you can see, I am setting the location ID.

NetsuiteUtil is a utility class I wrote to interface to the Web Service.