pc to unix FileExists function

[Rychertate]

How do handle the below? the files on the unix box can be pulled up through the URL. If I want to check if that file actually exists, how do I do that?
***********************************************

Dim fs, fExists, path
fExists = false
Set fs=Server.CreateObject("Scripting.FileSystemObject")
path = "

http://unixmachine.xxx.ppt"

response.write(path)
if fs.FileExists(path)=true then
fExists = True
response.write(path)
else
response.write("Didn't passed FileExists test")
end if

set fs=nothing

 

[Rychertate]

Is there an http link valid checker?