" The appref-ms file does not point to the exe. When you hit that shortcut, it invokes the deployment manifest at the deployment provider url and checks for updates.
It checks the application manifest (yourapp.exe.manifest) to see what files to download, and this file contains the definition of the entry point (i.e. the exe)."
My suggestion is first to move your Flixter desktop shortcut to a fixed place where to keep it (i.e. the application folder)
then directly from there drag the shortcut into the dock,
please try and let me know ! 
