There is no DOM method getElementByName - it is getElementsByName and it returns a collection, so you need to specify an item:
$username = InputBox("Message","Type Acc")
$password = InputBox("Message","Type Pass")
$oIE = ObjCreate("InternetExplorer.Application") ;
$oIE.visible = True ; show ie
$oIE.Navigate("[url="https://accounts.google.com/ServiceLogin?hl=en&continue=http://www.google.com.vn/"]https://accounts.google.com/ServiceLogin?hl=en&continue=http://www.google.com.vn/[/url]")
Sleep(10000)
$oIE.document.getElementById("Email").value=$username ; input acc
$oIE.document.getElementsByName("Passwd").Item(0).value=$password ; Input pass
$oIE.document.getElementById("signIn").click ; click button Login
Using the _IE functions from IE.au3 would likely simplify this for you.
Dale