I’m still stuck using Altiris 6.9DS.  It works, but it’s also finicky.  I often run into error 1618, which means another install is in progress (download the full error list here).  This is not always the case, but sometimes, other jobs can make it seem this way.  I run a simple command to clear out this error and then I can finish running the failing job.

taskkill /im msiexec.exe /f /t

It forcefully kills any msiexec process, allowing another install to begin.