Selim,

The GetAdaptersInfo function can be used only for the local computer.

To obtain MAC address for a LAN computer use either WMI Win32_NetworkAdapterConfiguration class or the NetWkstaTransportEnum function, as long as you have sufficient priviliges on accessing this computer.

oServer = GetObject("winmgmts:\\" + "SOMECOMPUTER" + "\root\cimv2") 
oAdapters = oServer.ExecQuery(; 
	"SELECT * FROM Win32_NetworkAdapterConfiguration")

Using NetWkstaTransportEnum to obtain MAC Address of remote server
http://www.news2news.com/vfp/?example=435

How to retrieve adapter information for the local computer (including MAC address)
http://www.news2news.com/vfp/?example=347&ver=wmi