[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.