Security Update for Windows Server 2003 (KB917344) fails to install

On one of my Windows SBS 2003 servers the Security Update for Windows Server
2003 (KB917344) is failing to install.

The relevant section from the windows update log is as follows:

2006-06-14 22:25:05 5752 16e4 Handler :: START :: Handler: Windows Patch
Install
2006-06-14 22:25:05 5752 16e4 Handler :::::::::
2006-06-14 22:25:05 5752 16e4 Handler : Updates to install = 1
2006-06-14 22:25:05 5752 16e4 Handler : Installing update
{AE1918E5-D860-439C-AE0B-6501BD043662}.102
2006-06-14 22:25:05 5752 16f4 Handler Installing with parameters=-q -z -er,
sandbox=C:\WINDOWS\SoftwareDistribution\Download\3 3f6d235559b1924eb7a50a0cf14fc55.
2006-06-14 22:25:12 5752 16f4 Handler Install completed with 0xd0000005.
2006-06-14 22:25:12 5752 16e4 Handler FATAL: UH: 0xd0000005:
InstallOrUninstallThread failed
2006-06-14 22:25:12 5752 16e4 Handler : WARNING: Install completed: result
type = 0x0, installer error = True, error = 0xd0000005, disabled until
reboot = No, reboot required = No
2006-06-14 22:25:12 5752 16e4 Handler FATAL: UH: 0x8024200b:
HandleSingleUpdate failed
2006-06-14 22:25:12 5752 16e4 Handler :::::::::
2006-06-14 22:25:12 5752 16e4 Handler :: END :: Handler: Windows Patch
Install

Any thoughts as to what's going on?
Thanks