Ad-Aware 2007 Professional Edition: By restarting the service, we can make the application compatible to RDS environment. Follow the link to know what remote desktop scenarios are supported Test details
Admin_MSFT :  [MSFT] This problem is observed when tested for the following scenario
Launch one instance of the application ad-aware 2007 with say Tim’s credentials, on the server.
Without closing the first session, launch another instance of the application with say Tom’s credentials. An error is observed in the second instance “System
Error:1814 has occured.Description:Could not login to service.Are you runnig the application as another user”
Admin_MSFT :  [MSFT] For issue multiple instance we use the workaround "need to restart the service" in the remote desktop Server.