Batch Files for Backup

I’m trying to write a simple batch file that takes data from my computer and backs it up on a server. I would like it to include subfolders as well.

COPY “C:\Documents and Settings\kfrost\My Documents\Documentation” “P:\Backups\kfrost”/S

I put this is notepad, saved it as a .bat and it doesn’t work. If I get rid of the /S it works fine but doesn’t copy any of my subfolders. I have XP pro on my desktop.
Any advice