While I don’t have a FVP5000T the basic point is that you cannot ping it fron your LAN, you have a problem. What is the IP and subnet masks of the humax, router, linkstation and device you initiated the ping on? Additionally what is the gateway IP of the Humax.
As you mention the Humax can share media from your linkstation I will presume the connection to the LAN is OK.
Other information that would be good to have is what OS is the 1PC running and idf recent have you enabled the program and features “SMB File sharing support”?