When You auto deploying Microsoft Forefront Client and on some computers installation fault. You should view log files on this computer \\computer name\c$\Program Files\Microsoft Forefront\Client Security\Client\Logs\Clientsetup.txt

Same examples from one computer:
2008-10-23 21:10:21 Microsoft Forefront Client Security (1.0.1703.0) — Installation started
2008-10-23 21:10:21 Hardware requirement check passed.
2008-10-23 21:10:21 OS requirement check passed.
2008-10-23 21:10:21 Software requirement check passed.
2008-10-23 21:10:21 The OS version running on the system is Windows XP SP2 without Filter Manager hotfix (KB914882). Hotfix KB914882 is required.
2008-10-23 21:10:21 Filter Manager installation failed.
2008-10-23 21:10:21 Microsoft Forefront Client Security — Installation failed.

We can see that Hotfix KB914882 is required. After installed this Hotfix deploying Microsoft Forefront Client completed successful.