I lost the connection beetween the controller and load Generator when i start an test. yet Icon in zones and load Genarators hosts is Green bullet.
If i launch the test second time the Connection is well established.
The green light only means that the load agent is available. But when you start a test it's another process that is started for the load generator.
If it works the second time then the issue might be that the LG process takes too much time to start and then the controller gives up.
You should check with the Windows task manager if a java.exe process is starting in the process list. Also make sure that you do not have an anti-virus that could slow down the starting of the load generator process.