The name of the executable is wrong. Also, I tested it and the part that focuses the game's window doesn't seem to work anymore. A proper working script would look like this:
Set WshShell = WScript.CreateObject("WScript.Shell")
obj = WshShell.Run("""scv3gs.exe""", 3, False)
WScript.sleep 9000
WshShell.SendKeys "%{ENTER}" 'Sends ALT+ENTER to enter in fulsscreen mode
Save as scv3gs.vbs, put it inside the game's root folder, then point Launchbox to that file instead of the game's exe. disable the Launchbox's startup screen if it gives you any trouble.
Edit: if the game takes too long to start, increase the WScript.sleep value from 9000 to 12000, 15000 or more.