I believe it’s a false positive, I have the same DLL (nexplayerx.dll) and it is part of my Samsung mobile phone software pack (it’s used by the integrated audio/video player). After a recent AVS update Avast started complaining this file is infected by Win32.Prex-Ac[wrm] but i’m quite confident that this is a a wrong virus detection.

Is it possible for Avast Team to check this out?