DIR/S and an UNC path

DIR fails when I try to list the files in
\\sillylongname.domain.com\directory\subdirectory
on Windows XP Spack2

I can see the files in z:\directory\subdirectory and I can see the
files with Windows Explorer with the exact path as specified above.
However, mapping will cause me problems in another pat of the batch
file I'm fixing, so I'd appreciate assistance from the collected
brainitude here on how to get a directory of files, including in
subordinate subdirectories, while specifying a UNC path, not a drive
letter, in a scriptt running from XP.

BTW, I have made sure Command Extensions were enabled....

Thank you kindly, all.