Do you have SSL enabled in your Altiris environment? One issue could be certificates aren't working correctly for the WinPE session to reach back to the server. Just a thought...
Logs are here in WinPE:
X:\Program Files\Symantec\Deployment\Logs
Open Notepad from the command line and set the option to Open "Files of Type" to "All Files". You'll see a few logs in there: "Pectgent" and "SMP", most likely. The SMP log should show whether it is reaching back successfully.