I have a problem (Access is denied) when I try to copy files across network in a Windows batch script.

Hudson will call a script, say, a.bat and inside a.bat I have the followings

...
setlocal ENABLEDELAYEDEXPANSION
...

if DEFINED abc (
   set xyz=\\computer\path
   set filename=mm*.dll

   copy /Y !xyz!\!filename!   
)
...
endlocal

The 'copy' command will fail and I Google for the problem but there's no particular one. There's one paper saying UNC should be used (http://stackoverflow.com/questions/1284561/hudson-continuous-integration-server-how-to-see-windows-mapped-directories-that). So I did the following experiments:

1) set xyz="//computer/path"
   ...
   copy /Y "!xyz!"\!filename!
2) ...
   copy /Y "//computer/path"\mm*.dll

The 1) doesn't work and produces the same problem - "Access is denied." but the 2) is working. However, copy /Y "//computer/path"!file_name! won't work either.