error on AD login after security update 2007-004

The macs in our school authenticate at an Active Directoy server. Students use both macs and windows pcs with their account. No additional software for directoy access is used on the mac client side as well as on the windows 2003 server side. after applying the security update 2004-007 every login attempt on every mac (G4,G5, Intel) the first login attempt after boot results in an error message (You are unable to log in to the user account at this time..." The error message in /var/log/system.log reads: Code display: [code] May 10 15:45:26 ibook-sk kernel[0]: netsmb_dev: loaded May 10 15:45:26 ibook-sk automount[222]: Can't mount sredu01.kzo.lokal:/HomesSchueler$ on /private/Network/Servers/sredu01.kzo.lokal/HomesSchueler$: Invalid argument (22) May 10 15:45:26 ibook-sk automount[222]: Attempt to mount /automount/Servers/sredu01.kzo.lokal/HomesSchueler$ returned 22 (Invalid argument) May 10 15:45:26 ibook-sk automount[157]: Can't mount sredu01.kzo.lokal:/HomesSchueler$ on /private/Network/Servers/sredu01.kzo.lokal/HomesSchueler$: Invalid argument (22) May 10 15:45:28 ibook-sk /System/Library/CoreServices/CCacheServer.app/Contents/MacOS/CCacheServer: Exiting: (os/kern) successful (0) [/code] The second attempt works fine and every following login with different users too. I have seen the problem mentioned at macfixit but all the suggested troubleshooting solutions didn't work. Has anybody seen this problem too? Even found a solution (not removing the update!)?