Saving file under IIS 7

[Excelgreenhand]

I am using the same logging id for saving file under
"c:\inetpub\wwwroot\file1.htm" --> This is working BUT when saving directly into the IIS server
"http://localhost/file1.htm" --> This failed and giving me error Run-time error '1004' Method 'SaveAs' of object' _Worksheet' failed.

I have given the permission of same logging id all permissions running Windows 7 Pro.

Anything I missed !? Please let me know.