I tried to work through a similar example and got it to work as follows:

Dim EMailRange As Range
Set EMailRange =
Workbooks("Book3.xls").Worksheets("Sheet1").Range( "A1:B1000")

Dim result As String
result = WorksheetFunction.VLookup(sServer, EMailRange, 2, False)

Just plug in your workbook & worksheet names & it should work.