[CentOS] replacing permissions on uploaded windows files

Hello, I've got a CentOS box and users are putting Windows long files on it, files with " " and " - " in their filenames. I'm trying to adjust the permissions as well as user and group membership and i'd like the changes to be sticky. On the tld i've set permissions of 2755 and am trying to batch convert the files and subfolders in it. I've done this:

find tld -type f |xargs chmod 644 {} ; find tld -type d |xargs chmod 755 {} ;

Both of these are failing due to the spaces and dashes. I've tried enclosing those {} in quotes, no good. Has anyone done this with shell or perhaps perl? Thanks. Dave.