Account lockout - analysis help

[gary () aspectcapital com]

Hi,

I Have a user who keeps getting his account locked out, but I cannot work out why. I use the alockout tools, to get me 
the following 

Wed Jan 17 08:40:00 2007, PID:  1872, Thread:  2284, Image xcopy,ALOCKOUT.DLL - DLL_PROCESS_ATTACH
Wed Jan 17 08:40:12 2007, PID:  1872, Thread:  2284, Image xcopy,ALOCKOUT.DLL - dll_process_detatch
Wed Jan 17 09:50:29 2007, PID:  3216, Thread:  2920, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
DLL_PROCESS_ATTACH
Wed Jan 17 09:50:29 2007, PID:  3216, Thread:  2920, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
dll_process_detatch
Wed Jan 17 09:52:19 2007, PID:  2648, Thread:  3160, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
DLL_PROCESS_ATTACH
Wed Jan 17 09:52:20 2007, PID:  2648, Thread:  3160, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
dll_process_detatch
Wed Jan 17 09:53:32 2007, PID:  2040, Thread:  1388, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
DLL_PROCESS_ATTACH
Wed Jan 17 09:53:33 2007, PID:  2040, Thread:  1388, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
dll_process_detatch
Wed Jan 17 09:53:57 2007, PID:  2264, Thread:  2060, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
DLL_PROCESS_ATTACH
Wed Jan 17 09:53:58 2007, PID:  2264, Thread:  2060, Image C:\PROGRA~1\MICROS~4\OFFICE11\OUTLOOK.EXE,ALOCKOUT.DLL - 
dll_process_detatch
Wed Jan 17 09:54:15 2007, PID:   656, Thread:  3368, Image taskmgr.exe,ALOCKOUT.DLL - DLL_PROCESS_ATTACH
Wed Jan 17 09:54:41 2007, PID:   656, Thread:  3368, Image taskmgr.exe,ALOCKOUT.DLL - dll_process_detatch.

Looking on my dc's I hae the following entries 

Service Ticket Request Failed:
        User Name:      shallensleben
        User Domain:    ASPECTCAPITAL.COM
        Service Name:   exchangeMDB/VEGA2
        Ticket Options: 0x40800000
        Failure Code:   0x12
        Client Address: 172.16.x.x

Authentication Ticket Request Failed:
        User Name:      shallensleben
        Supplied Realm Name:    ASPECTCAPITAL.COM
        Service Name:   krbtgt/ASPECTCAPITAL.COM
        Ticket Options: 0x40810010
        Failure Code:   0x12
        Client Address: 172.16.x.x

I have also checked for the obvious mapped netowrk drives, runas, saving credentials etc. all of which are absent.

This is the only user in the domain that gets locked out. He does switch between out wireless and network environment, 
which I believe should not contribute to the problem?

Does anyone have any ideas?

Thanks in advance,