, lensman wrote

Also consider that asp.net apps operate within a sand box.  Your thread might not have rights to view the destination location. 

 I think you may just be right about that. This is an exception I got from a File.Delete in another thread spawned:
"The account used is a computer account. Use your global user account or local user account to access this server.  "

And blowdart comes to the rescue yet again, you're awesome, thanks.