Referencing a closed workbook

Hi Everyone,

Please can someone tell me what's causing the syntax error when I try and set the string named 'arg' as a reference to cell A1 of a closed workbook?

Sub Test2()

Dim arg As String

'next line is a syntax error

arg = 'E:\archive\[test.xlsx]Sheet1'! & Range("A1").Range("A1").Address(, , xlR1C1)


ActiveSheet.Range("A1") = ExecuteExcel4Macro(arg)


End Sub

Help much appreciated,

Thanks,

Rowan