Sorry, it's difficult to help because I don't really understand the code or what you are trying to do. Troubleshooting custom code is beyond the scope of what we can help with on the forum.
I'm not sure this is going to make things work the way you want but to avoid the error remove the transport object, which is called 'GrabObj' in the line below:
Code:
viznet.client.sendAll(UPDATE,client=viz.getComputerName(),pos=pos,ori=ori,GrabObj=GrabObj,DisAssPart=DisAssPart )
It seems like you are already sending the position and orientation of the transport and there is only one transport used in the script. So in your function that receives the network data, get a handle to that transport and then call set position and orientation on it.
Maybe there's an easier way of setting this up. Can you explain generally how your application is supposed to work? We can't necessarily provide code but may have suggestions.