I am in similar situation. I have a ESET Remote Administrator Appliance (Centos 6.7) up and running. On the client side the ESET Remote Administrator Agent is running -- flawlessly.
When i try to run a task with ESET Endpoint Antivirus 6 installation, it fails. Contrary to the Marcos post at 22 June 2015 - 02:01 PM, if i try a local installation with Offline installer, it works.
Moreover, if i try to activate this EEA6 by the means of ESET Remote Administrator, it fails too.
Client system is domain-joined Windows 7 Professional 32bit.