Add a new task to your deployment.  "Modify Configuration" and then you can add it to the domain from the "Microsoft networking" section.  That is the recommended way to do that.

I've seen this be an issue if the AClient/DAgent are not the same version as the DS.  You might ensure that they are the same build.

Aen, bhawver
how do I check the versions of these applications?  is there anything else we can do to get these to authenticate and be added to the domain? 

thx!

On the client side of things, either double click on the tray icon (if you have not hidden it) and it will be listed near the top (i.e. mine says "Altiris Client Service for Windows (Version 6.9.366)(x86).  If you have hidden the icon from your users, you can open your Windows Explorer and explore to "c:\program files\altiris" and right-click on aclient.exe and click on the version tab.

On the DS side of things, in the console, just do Help-->About.  The version information should be there.  Make sure the two match.

You can also check the agent on the DS side.  Just right click on the computer and go to properties.  On the first page under "Windows agent version" it will show the version of the acleint.  You can compair this to what bhawver said above about the server version.  Also if it has the update job schedule that is usally a good indication =P.

bhawver, spazzzen
thanx for hanging with me on this, but I'm not making progress. 

both the client and DS versions are the same. 

In my ReplaceTokens file, I have the following.  do I need quotes around each entry or not? 
is this even doing anything when it's trasfered to the sysprep file? 

[Identification]
     JoinDomain="Stras.cc"
     DomaniAdmin="stras.cc\Alt"
     DomainAdminPassword="blabla"
     MachineObjectOU="OU=IT,DC=Stras,DC=cc"

Everything else seems to be working...just not being added to the domain. 

thx!

The quotes are not needed.  Also, you do not need the stras.cc infront of your domain admin account.  It is assumed that the Domain Admin is part of the supplied domain  This could be the cause of it failing, but then again it may not be.  You might also want to check that the network driver is being installed correctly by Sysprep.  I ran into some problems a little while back where everything looked good until you brought up the device manager and realized the NIC was not installed.

Hope this helps,
Pikoshi

After re-reading your initial post I noticed something that may or may not be causing a problem.  I noticed that you are pointing to a "Computers" OU.  If this is the default area in Active Directory, it is a folder not an OU.  Is it possible that AD does not understand Altiris during the join domain?

That being said, to test this theory would be to create a specific OU (not a folder) in AD and try to join directly to that OU.  If that works, then you know that your problem is related to the OU that you were pointing and the fact that it was not an OU.