Fellow SMB'ers'

I've been using Samba successfully for over ten years now. On ONE of
my servers running AIX 5.1 and Samba 2.2.1 I can make a connection
from Win98SE/ME/XP and "SEE" the files on the server. However, if I
try to open ANY of the files shown I receive a message stating that
"the file cannot be found. Do I want to create a file".

Here is my current smb.conf file content for this server:
# Global parameters
log file = /var/samba/log.%m
client code page = 437
guest account = Nobody
socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
browse list = yes
interfaces =
domain master = no
encrypt passwords = yes
hosts allow = 192.168.0., 65.75.16.xxx, 63.148.38.xxx
public = yes
lock dir = /var/samba/locks
local master = no
workgroup = xxx
os level = 255
security = user
log level = 1

writeable = yes
path = /usr/xxx
force directory mode = 0777
sync always = yes
force create mode = 0777
force user = xxxxx
readonly = no
create mode = 0777
directory mode = 0777
case sensitive = yes

All my other servers are Linux (RH8 and SuSE9) and I can access and
use those files without issue. What may have changed on the AIX box
and can anyone "see" anything in error in the conf file?