I encounter this error whenever I resume from standby on my Eee PC. After checking online, I found it is related to Atheros Configuration Service.
It gives access to single sign on and a mechanism to communicate with the supplicant for security negotiation.
As I prefer to use Windows to configure my wireless network settings, I have disabled ACU from startup. To remove the error, I have stopped this service from running and changed the startup from automatic to manual.