Insert an image into a PDF. Acces denied! System.UnauthorizedAccessException:

Hi, I'm trying to insert an image into a PDF, when I'm creating it.
It works fine at localhost. But when I try i on server, it crash at the line of inserting image.
I've tried with:
Dim stream As IO.Stream = IO.File.Open(Server.MapPath("~/Imagenes/Cabeceras/LogoPresfiap.jpg"), IO.FileMode.Open)
or

Dim stream As IO.Stream = IO.File.Open(Server.MapPath("~/../../Cabeceras/LogoPresfiap.jpg"), IO.FileMode.Open)


No sucess. It throws me an error Acces denied:
[UnauthorizedAccessException: Acceso denegado a la ruta de acceso 'F:\WebCOAATIE\Imagenes\Cabeceras\LogoPresfiap.jpg'.]
System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) +10544291
System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, ...