Apple - Discussions - 10.3.9 problem with multiple users
This is a nasty one. Systems start having login problems - non-admin accounts can't login. On my 10.3.9 system I haven't had this problem, but I've discovered folders in ./Library/ that have a non-admin owner and the admin group has read-only privileges. This doesn't make sense.
Repair permissins doesn't fix the problem. I suspect it has something to do with the 'floating ownership' behavior in OS X -- that may have been broken in 10.3.9.
Based on the desccriptions of this problem in the Apple discussion forums, and the lack of a fix for over a week, I'd recommend NOT updating to 10.3.9 until this is fixed.