GameObject becomes invalid

So, i tried to make a simple client - server comunication in Blender. Now i have the client sending the states of the keys to the server, and the server has an object that do some movement when some keys are pressed. I tried to make a car object in the server, and to view the car in the client, i decided to apply the code to the client object too. But when i run the Vehicle Wrapper code, the client code shows an error when it tries to set the position to the player entities in the scene. The error is “Blender Game Engine data has been freed, cannot use this python variable”. I found on the web that this happens when the object becomes “Invalid”. I thought that could be the making of the subclassing of the GameObject, but if i don’t run the VW code, it works with the subclass as well. Is there a way to solve this?

Sorry for my bad English.