Hello Joseph,

Patch for Mac takes advantage of the Task Server technology and all of the flexibility of which it is capable.  That said, the sky is pretty much the limit as to the customizations you can make.  For example, I put together this client job, which in theory, will install all updates on a Mac that has nobody logged on, and after is has "locked" the screen (using your provided code).  For the "UserLoggedOn" task, I used the Run Script template and put in some shell script code to check to see if a user was logged in or not (using the 'who' command combined with 'grep').  The "Disable Logins" and "Re-enable Logins" tasks also used the Run Script template and use the code you provided above.  All of this started by cloning the "Install all available updates" job which is where you have started as well.  Hopefully, this will help you a bit in your quest...:-)

BTW, the code I used for the UserLoggedOn script is this:

#!/bin/sh


# If no users are logged on then it will exit 0

if who | egrep $1 $2 >/dev/null 2>&1;

then
   echo 0

else
   echo 1

fi 

Thank you very much for your help, however the "Install all available updates_1" task keeps failing when I run the job. The first time I ran it the code was 3, the second time it was 2. All subsequent attempts error out with code 2

It worked just fine for me.  I have a MBP here that needed Safari 4.0.4 and the job worked like a charm.  Is the Mac your testing configured to pull the updates from a local SUS or from apple.com directly? 

Not sure if this would cause it or not, but the code I posted for the UserLoggedOn script isn't entirely correct.  See above.  The "echo" commands should be "exit". 

 Use "aex-configure" to increase the log level on the client.  It can be found under /opt/altiris/notification/nsagent/bin.  The NS agent will need to be stopped first so run './rcscript stop'.  Then, simply run './aex-configure -iconfigure' and carefully go through the different prompts.  One will ask you the level of logging you wish to enable.

not very informative:

ERRO 2009-11-16 13:28:38.988     13104    2685957920  Install > InstallCommand::Run() - commandEngine.Run() failed, rc = 2. 

Here are my agent versions:

 Here are the specific return codes that relate to Patch for Mac.  If you are getting negative values for return codes, that might be Task Server specific or just generic UNIX system codes.  What are the results of the "Obtain Console Output" sub task?