fix the null case for deep copy

OpenSim/Data/NHibernate/TextureUserType.cs

@@ -48,10 +48,18 @@ namespace OpenSim.Data.NHibernate
         }
 
         public object DeepCopy(object texture)
+        {
+            if (texture == null) 
+            {
+                // TODO: should parametrize this texture out
+                return new LLObject.TextureEntry(new LLUUID("89556747-24cb-43ed-920b-47caed15465f"));
+            }
+            else 
             {
                 byte[] bytes = ((LLObject.TextureEntry)texture).ToBytes();
                 return new LLObject.TextureEntry(bytes, 0, bytes.Length);
             }
+        }
 
         public object Disassemble(object texture)
         {