Those who installed Samba on RHEL or any other SELinux enabled distribution may have faced the problem when they actually cannot access any Samba shares from their Windows machines. Samba logs in /var/samba/log may show lots of such messages:
[2007/07/03 16:37:44, 0] smbd/service.c:make_connection_snum(911) ‘/opt/blah’ does not exist or permission denied when connecting to [blah] [...]