AutoCAD .NET :: Adding Entity On New Drawing (document) With New Layer

I am trying to add an entity on a new drawing (document) with a new layer.

Following is the code snippet I have right now.
 
[CommandMethod("TEST")] public void Test() { Document newDoc = Application.DocumentManager.Add("acad"); Database db = newDoc.Database; DocumentLock docLock = newDoc.LockDocument(); try { using (Transaction tr = db.TransactionManager.StartTransaction()) { BlockTable bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as [code]..........

PTPUtils.CreateLayer() method creates a new layer in the given DB. However, the code gives me an "eKeyNotFound" exception in the line p.Layer = newLayer.

If I remove the p.Layer line, the code works very well. But the entity only goes to the default layer "0".