A common cause of these errors on Avalanche appliance hardware occurs when no ports, or incorrect ports are reserved for the test. To reserve ports from Avalanche Commander select 'Administration' -> 'Appliances' -> 'User Administration' and right click on the ports you wish to use for your test.
If correct port reservation does not resolve please ensure your Avalanche Commander and Appliance version are not mismatched as this could also result in the error.