Permissions Problems Between Samba and NFS

I am running FC3 on a production server that needs to be accessible from both PC and Mac OS X clients. I originally tried using Samba for both, but the Macs always had intermittent problems with the Samba shares, so I switched to exporting the same shares via NFS and then using Samba for the PCs. However, once I did this, I ran into a situation where the Macs can not write to any directories or files that have been created by Samba.

For example, if I make a folder on the server with Mac A, then both Mac B and a PC can write to it just fine.

However, if I make a folder on the server with the PC, neither Mac is able to write to the folder.

Here is what I have for /etc/samba/smb.conf right now:

[global]
   workgroup = workgroup
   server string = Name
   hosts allow = 192.168.0. 127.
   printcap name = /etc/printcap
   load printers = no
;   printing = cups
cups options = raw
;  guest account = pcguest
 log file = /var/log/samba/%m.log
   max log size = 50
   security = user
   socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
   local master = yes
   dns proxy = no

#============================ Share Definitions ==============================
   idmap uid = 16777216-33554431
   idmap gid = 16777216-33554431
   template shell = /bin/false
   winbind use default domain = no

[Share]
 path = /raid/share
 guest ok = yes
 public = yes
 writable = yes

If anybody could offer any suggestions, that would be most welcome.

Thanks!

Shane