Cannot write to Samba share regardless of permissions

Please help! We have an isolated mixed environment where we are trying to use Samba on Red Hat 6.5 to create shares for Windows clients. We have this implemented in a number of locations and it works fine, but I am trying to build another system and for the life of me I cannot get it to work. I have mimicked the Samba settings... the file and ownership settings are the same, but on the new server, no matter what I do I can only see folder and I cannot write anything despite the following settings in smb.conf:

[QA_TestData]
writeable = yes
public = yes
create mode = 777
path = /mnt/QA/QA_TestData
directory mode = 777

Samba global settings are:

[global]
log file = /var/log/samba/log.%m
load printers = yes
cups options = raw
netbios name = QA-US-LINUX01
server string = Samba Server Version %v
writeable = yes
os level = 20
create mode = 777
security = share
public = yes
passdb backend = tdbsam
max log size = 50
directory mode = 777

What am I doing wrong? It shouldnt take me 2 days to create a wide open Samba share.....