Samba folders (not share) access denied from Vista only with hostname

Hello,

I am seeing a strange problem with Vista and Samba and I was wondering
if anyone may know what is causing this. If I access my Samba server
from Vista using the hostname I can access the share but I cannot
access any folders in the share that do not have rwx permissions to my
primary group. If I access the same server by IP I can access all the
appropriate folders. If I access the server (this is happening on 2
servers) from Win XP/2003/2000/Mac/Linux everything works fine.

For example. I access \\SERVERNAME\SHARE and I double click on a
folder named Accounting I get an access denied yet the folder has rwx
for the accounting group enabled and I am a member of the Accounting
group. So I double click on the folder called "Drop Box" which has rwx
for Domain Users and I can access the directory.

Next if I access the same server by IP \ SHARE I can access all the
correct folders.

Both of these servers have been production for a long time and I can
verify that this is all working for every client EXCEPT for Vista.

FYI- HAve tried disableing UAC and am using NTLMv1.

Does anyone know what could be causing this?