Fedora join to AD DS (svr 2008): NT_STATUS_INVALID_COMPUTER_NAME

I have been attempting to join my Fedora machine to my 2008 AD DS domain (testdomain.lcl) for some time now. I have followed this article:

http://weblog.bignerdranch.com/?p=6

But with no luck. I have also tried Likewise. The error I am getting is "Error in domain join verification (credential setup failed): NT_Status_Invalid_Computer_Name.

I have one server on which I've set up AD DS, DNS, and DHCP services. I have verified that the Fedora machine is getting an IP and I can do an nslookup to the domain controller.

Here are the relevant parts of my smb.conf file:

workgroup=testdomain
password server=192.168.1.2
realm=TESTDOMAIN
security=ads
idmap uid=16777216-33554431
idman-gid=16777216-33554431
template shell=/sbin/nologin
winbind use default domain=false
winbind offline logon=false