the other machine is used just to be connected on RDP..
the normal connection when established, is maintained untill i close the session.. as longer as i want..
for the moment there are no problem, hoping that it will not occure again (session closed and black screen), if not yes i will uninstall the agent to try 
version of view 5.2, vcenter 5.1 u1, esx 5.1, client is windows seven
best regard,