Server is for ASP coding, you can remove it, try that:
'Add a reference to Microsoft Scripting Runtime
Dim fso As New FileSystemObject
MsgBox fso.GetAbsolutePathName("D:"), , "REFERENCE"
Set fso2 = CreateObject("Scripting.FileSystemObject")
MsgBox fso2.GetAbsolutePathName("D:"), , "W/O REFERENCE"
See the first method, by using a reference, it might work better since your object is declared as a FileSystemObject and not as a Object